diff --git a/BUILDING_FROM_SOURCE.md b/BUILDING_FROM_SOURCE.md
index bb1e70733c..4182939e77 100644
--- a/BUILDING_FROM_SOURCE.md
+++ b/BUILDING_FROM_SOURCE.md
@@ -109,7 +109,7 @@ Alternatively, you can use `cargo test --no-fail-fast` or `cargo test -p specifi
 
 For debugging LLVM IR, we use [DebugIR](https://github.com/vaivaswatha/debugir). This dependency is only required to build with the `--debug` flag, and for normal developtment you should be fine without it.
 
-### libcxb libraries
+### libxcb libraries
 
 You may see an error like this during builds:
 
diff --git a/compiler/builtins/README.md b/compiler/builtins/README.md
index ceaf3007e3..2ab95cd260 100644
--- a/compiler/builtins/README.md
+++ b/compiler/builtins/README.md
@@ -60,7 +60,7 @@ Its one thing to actually write these functions, its _another_ thing to let the
 
 ## Specifying how we pass args to the function
 ### builtins/mono/src/borrow.rs
-After we have all of this, we need to specify if the arguments we're passing are owned, borrowed or irrelevant. Towards the bottom of this file, add a new case for you builtin and specify each arg. Be sure to read the comment, as it explains this in more detail.
+After we have all of this, we need to specify if the arguments we're passing are owned, borrowed or irrelevant. Towards the bottom of this file, add a new case for your builtin and specify each arg. Be sure to read the comment, as it explains this in more detail.
 
 ## Testing it
 ### solve/tests/solve_expr.rs
@@ -87,7 +87,7 @@ In this directory, there are a couple files like `gen_num.rs`, `gen_str.rs`, etc
 fn atan() {
     assert_evals_to!("Num.atan 10", 1.4711276743037347, f64);
 }
-    ```
+```
 But replace `Num.atan`, the return value, and the return type with your new builtin.
 
 # Mistakes that are easy to make!!
diff --git a/compiler/builtins/bitcode/src/dec.zig b/compiler/builtins/bitcode/src/dec.zig
index 2f0dcb6abe..b9eba9c0cc 100644
--- a/compiler/builtins/bitcode/src/dec.zig
+++ b/compiler/builtins/bitcode/src/dec.zig
@@ -310,9 +310,7 @@ pub const RocDec = extern struct {
 
         // (n / 0) is an error
         if (denominator_i128 == 0) {
-            // The compiler frontend does the `denominator == 0` check for us,
-            // therefore this case is unreachable from roc user code
-            unreachable;
+            @panic("TODO runtime exception for dividing by 0!");
         }
 
         // If they're both negative, or if neither is negative, the final answer
diff --git a/compiler/builtins/bitcode/src/num.zig b/compiler/builtins/bitcode/src/num.zig
index 41d93df976..54bcf8ff5a 100644
--- a/compiler/builtins/bitcode/src/num.zig
+++ b/compiler/builtins/bitcode/src/num.zig
@@ -102,7 +102,7 @@ pub fn exportRound(comptime T: type, comptime name: []const u8) void {
 pub fn exportDivCeil(comptime T: type, comptime name: []const u8) void {
     comptime var f = struct {
         fn func(a: T, b: T) callconv(.C) T {
-            return math.divCeil(T, a, b) catch unreachable;
+            return math.divCeil(T, a, b) catch @panic("TODO runtime exception for dividing by 0!");
         }
     }.func;
     @export(f, .{ .name = name ++ @typeName(T), .linkage = .Strong });
diff --git a/compiler/builtins/docs/Num.roc b/compiler/builtins/docs/Num.roc
index 2f45e22600..2e4b78708f 100644
--- a/compiler/builtins/docs/Num.roc
+++ b/compiler/builtins/docs/Num.roc
@@ -81,8 +81,6 @@ interface Num
             minI64,
             minU64,
             minI128,
-            modInt,
-            modFloat,
             mul,
             mulChecked,
             mulWrap,
diff --git a/compiler/builtins/roc/Num.roc b/compiler/builtins/roc/Num.roc
index 1cbba15026..1d1102d8fe 100644
--- a/compiler/builtins/roc/Num.roc
+++ b/compiler/builtins/roc/Num.roc
@@ -67,6 +67,7 @@ interface Num
             isNegative,
             rem,
             div,
+            divChecked,
             sqrt,
             log,
             round,
@@ -93,7 +94,9 @@ interface Num
             bytesToU16,
             bytesToU32,
             divCeil,
+            divCeilChecked,
             divFloor,
+            divFloorChecked,
             toStr,
             isMultipleOf,
             minI8,
@@ -238,10 +241,13 @@ atan : Float a -> Float a
 
 sqrt : Float a -> Result (Float a) [ SqrtOfNegative ]*
 log : Float a -> Result (Float a) [ LogNeedsPositive ]*
-div : Float a, Float a -> Result (Float a) [ DivByZero ]*
+div : Float a, Float a -> Float a
+divChecked : Float a, Float a -> Result (Float a) [ DivByZero ]*
 
-divCeil: Int a, Int a -> Result (Int a) [ DivByZero ]*
-divFloor: Int a, Int a -> Result (Int a) [ DivByZero ]*
+divCeil : Int a, Int a -> Int a
+divCeilChecked : Int a, Int a -> Result (Int a) [ DivByZero ]*
+divFloor : Int a, Int a -> Int a
+divFloorChecked : Int a, Int a -> Result (Int a) [ DivByZero ]*
 # mod : Float a, Float a -> Result (Float a) [ DivByZero ]*
 
 rem : Int a, Int a -> Result (Int a) [ DivByZero ]*
diff --git a/compiler/builtins/src/std.rs b/compiler/builtins/src/std.rs
index 8659f19d12..5a8be89856 100644
--- a/compiler/builtins/src/std.rs
+++ b/compiler/builtins/src/std.rs
@@ -316,17 +316,31 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         Box::new(SolvedType::Wildcard),
     );
 
-    // divInt : Int a, Int a -> Result (Int a) [ DivByZero ]*
+    // divInt : Int a, Int a -> Int a
     add_top_level_function_type!(
         Symbol::NUM_DIV_INT,
         vec![int_type(flex(TVAR1)), int_type(flex(TVAR1))],
+        Box::new(int_type(flex(TVAR1)))
+    );
+
+    // divIntChecked : Int a, Int a -> Result (Int a) [ DivByZero ]*
+    add_top_level_function_type!(
+        Symbol::NUM_DIV_INT_CHECKED,
+        vec![int_type(flex(TVAR1)), int_type(flex(TVAR1))],
         Box::new(result_type(int_type(flex(TVAR1)), div_by_zero.clone())),
     );
 
-    // divCeil: Int a, Int a -> Result (Int a) [ DivByZero ]*
+    // divCeil : Int a, Int a -> Int a
     add_top_level_function_type!(
         Symbol::NUM_DIV_CEIL,
         vec![int_type(flex(TVAR1)), int_type(flex(TVAR1))],
+        Box::new(int_type(flex(TVAR1)))
+    );
+
+    //divCeilChecked : Int a, Int a -> Result (Int a) [ DivByZero ]*
+    add_top_level_function_type!(
+        Symbol::NUM_DIV_CEIL_CHECKED,
+        vec![int_type(flex(TVAR1)), int_type(flex(TVAR1))],
         Box::new(result_type(int_type(flex(TVAR1)), div_by_zero.clone())),
     );
 
@@ -659,6 +673,13 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
     add_top_level_function_type!(
         Symbol::NUM_DIV_FLOAT,
         vec![float_type(flex(TVAR1)), float_type(flex(TVAR1))],
+        Box::new(float_type(flex(TVAR1)))
+    );
+
+    // divChecked : Float a, Float a -> Result (Float a) [ DivByZero ]*
+    add_top_level_function_type!(
+        Symbol::NUM_DIV_FLOAT_CHECKED,
+        vec![float_type(flex(TVAR1)), float_type(flex(TVAR1))],
         Box::new(result_type(float_type(flex(TVAR1)), div_by_zero.clone())),
     );
 
diff --git a/compiler/can/src/builtins.rs b/compiler/can/src/builtins.rs
index 19a2896dc6..57de898cf5 100644
--- a/compiler/can/src/builtins.rs
+++ b/compiler/can/src/builtins.rs
@@ -196,8 +196,11 @@ pub fn builtin_defs_map(symbol: Symbol, var_store: &mut VarStore) -> Option<Def>
         NUM_COS => num_cos,
         NUM_TAN => num_tan,
         NUM_DIV_FLOAT => num_div_float,
+        NUM_DIV_FLOAT_CHECKED => num_div_float_checked,
         NUM_DIV_INT => num_div_int,
+        NUM_DIV_INT_CHECKED => num_div_int_checked,
         NUM_DIV_CEIL => num_div_ceil,
+        NUM_DIV_CEIL_CHECKED => num_div_ceil_checked,
         NUM_ABS => num_abs,
         NUM_NEG => num_neg,
         NUM_REM => num_rem,
@@ -4183,8 +4186,13 @@ fn num_abs(symbol: Symbol, var_store: &mut VarStore) -> Def {
     )
 }
 
-/// Num.div : Float, Float -> Result Float [ DivByZero ]*
+/// Num.div : Float, Float -> Float
 fn num_div_float(symbol: Symbol, var_store: &mut VarStore) -> Def {
+    num_binop(symbol, var_store, LowLevel::NumDivUnchecked)
+}
+
+/// Num.divChecked : Float, Float -> Result Float [ DivByZero ]*
+fn num_div_float_checked(symbol: Symbol, var_store: &mut VarStore) -> Def {
     let bool_var = var_store.fresh();
     let num_var = var_store.fresh();
     let unbound_zero_var = var_store.fresh();
@@ -4249,8 +4257,13 @@ fn num_div_float(symbol: Symbol, var_store: &mut VarStore) -> Def {
     )
 }
 
-/// Num.div : Int a , Int a -> Result (Int a) [ DivByZero ]*
+/// Num.div : Int a, Int a -> Int a
 fn num_div_int(symbol: Symbol, var_store: &mut VarStore) -> Def {
+    num_binop(symbol, var_store, LowLevel::NumDivUnchecked)
+}
+
+/// Num.divChecked : Int a , Int a -> Result (Int a) [ DivByZero ]*
+fn num_div_int_checked(symbol: Symbol, var_store: &mut VarStore) -> Def {
     let bool_var = var_store.fresh();
     let num_var = var_store.fresh();
     let unbound_zero_var = var_store.fresh();
@@ -4320,8 +4333,13 @@ fn num_div_int(symbol: Symbol, var_store: &mut VarStore) -> Def {
     )
 }
 
-/// Num.divCeil : Int a , Int a -> Result (Int a) [ DivByZero ]*
+/// Num.divCeil : Int a, Int a -> Int a
 fn num_div_ceil(symbol: Symbol, var_store: &mut VarStore) -> Def {
+    num_binop(symbol, var_store, LowLevel::NumDivCeilUnchecked)
+}
+
+/// Num.divCeilChecked : Int a , Int a -> Result (Int a) [ DivByZero ]*
+fn num_div_ceil_checked(symbol: Symbol, var_store: &mut VarStore) -> Def {
     let bool_var = var_store.fresh();
     let num_var = var_store.fresh();
     let unbound_zero_var = var_store.fresh();
diff --git a/compiler/load_internal/src/file.rs b/compiler/load_internal/src/file.rs
index 380099174a..28f5e9c2e8 100644
--- a/compiler/load_internal/src/file.rs
+++ b/compiler/load_internal/src/file.rs
@@ -3598,17 +3598,14 @@ fn run_solve<'a>(
     let (solved_subs, exposed_vars_by_symbol, problems) = {
         if module_id.is_builtin() {
             match cached_subs.lock().remove(&module_id) {
-                None => {
-                    // this should never happen
-                    run_solve_solve(
-                        imported_builtins,
-                        exposed_for_module,
-                        constraints,
-                        constraint,
-                        var_store,
-                        module,
-                    )
-                }
+                None => run_solve_solve(
+                    imported_builtins,
+                    exposed_for_module,
+                    constraints,
+                    constraint,
+                    var_store,
+                    module,
+                ),
                 Some((subs, exposed_vars_by_symbol)) => {
                     (Solved(subs), exposed_vars_by_symbol.to_vec(), vec![])
                 }
diff --git a/compiler/load_internal/tests/test_load.rs b/compiler/load_internal/tests/test_load.rs
index f78802553c..8f0223d483 100644
--- a/compiler/load_internal/tests/test_load.rs
+++ b/compiler/load_internal/tests/test_load.rs
@@ -426,12 +426,12 @@ mod test_load {
             loaded_module,
             hashmap! {
                 "floatTest" => "Float *",
-                "divisionFn" => "Float a, Float a -> Result (Float a) [ DivByZero ]*",
-                "divisionTest" => "Result (Float *) [ DivByZero ]*",
+                "divisionFn" => "Float a, Float a -> Float a",
+                "divisionTest" => "Float *",
                 "intTest" => "I64",
                 "x" => "Float *",
                 "constantNum" => "Num *",
-                "divDep1ByDep2" => "Result (Float *) [ DivByZero ]*",
+                "divDep1ByDep2" => "Float *",
                 "fromDep2" => "Float *",
             },
         );
diff --git a/compiler/module/src/low_level.rs b/compiler/module/src/low_level.rs
index c0d39f41b3..b15f8e682f 100644
--- a/compiler/module/src/low_level.rs
+++ b/compiler/module/src/low_level.rs
@@ -290,8 +290,10 @@ impl LowLevelWrapperType {
             Symbol::NUM_LT => CanBeReplacedBy(NumLt),
             Symbol::NUM_LTE => CanBeReplacedBy(NumLte),
             Symbol::NUM_COMPARE => CanBeReplacedBy(NumCompare),
-            Symbol::NUM_DIV_FLOAT => WrapperIsRequired,
-            Symbol::NUM_DIV_CEIL => WrapperIsRequired,
+            Symbol::NUM_DIV_FLOAT => CanBeReplacedBy(NumDivUnchecked),
+            Symbol::NUM_DIV_FLOAT_CHECKED => WrapperIsRequired,
+            Symbol::NUM_DIV_CEIL => CanBeReplacedBy(NumDivCeilUnchecked),
+            Symbol::NUM_DIV_CEIL_CHECKED => WrapperIsRequired,
             Symbol::NUM_REM => WrapperIsRequired,
             Symbol::NUM_IS_MULTIPLE_OF => CanBeReplacedBy(NumIsMultipleOf),
             Symbol::NUM_ABS => CanBeReplacedBy(NumAbs),
diff --git a/compiler/module/src/symbol.rs b/compiler/module/src/symbol.rs
index c66fa0f090..cadd3ea782 100644
--- a/compiler/module/src/symbol.rs
+++ b/compiler/module/src/symbol.rs
@@ -945,118 +945,126 @@ define_builtins! {
         36 NUM_IS_POSITIVE: "isPositive"
         37 NUM_IS_NEGATIVE: "isNegative"
         38 NUM_REM: "rem"
-        39 NUM_DIV_FLOAT: "div"
-        40 NUM_DIV_INT: "divFloor"
-        41 NUM_MOD_INT: "modInt"
-        42 NUM_MOD_FLOAT: "modFloat"
-        43 NUM_SQRT: "sqrt"
-        44 NUM_LOG: "log"
-        45 NUM_ROUND: "round"
-        46 NUM_COMPARE: "compare"
-        47 NUM_POW: "pow"
-        48 NUM_CEILING: "ceiling"
-        49 NUM_POW_INT: "powInt"
-        50 NUM_FLOOR: "floor"
-        51 NUM_ADD_WRAP: "addWrap"
-        52 NUM_ADD_CHECKED: "addChecked"
-        53 NUM_ADD_SATURATED: "addSaturated"
-        54 NUM_ATAN: "atan"
-        55 NUM_ACOS: "acos"
-        56 NUM_ASIN: "asin"
-        57 NUM_AT_SIGNED128: "@Signed128"
-        58 NUM_SIGNED128: "Signed128"
-        59 NUM_AT_SIGNED64: "@Signed64"
-        60 NUM_SIGNED64: "Signed64"
-        61 NUM_AT_SIGNED32: "@Signed32"
-        62 NUM_SIGNED32: "Signed32"
-        63 NUM_AT_SIGNED16: "@Signed16"
-        64 NUM_SIGNED16: "Signed16"
-        65 NUM_AT_SIGNED8: "@Signed8"
-        66 NUM_SIGNED8: "Signed8"
-        67 NUM_AT_UNSIGNED128: "@Unsigned128"
-        68 NUM_UNSIGNED128: "Unsigned128"
-        69 NUM_AT_UNSIGNED64: "@Unsigned64"
-        70 NUM_UNSIGNED64: "Unsigned64"
-        71 NUM_AT_UNSIGNED32: "@Unsigned32"
-        72 NUM_UNSIGNED32: "Unsigned32"
-        73 NUM_AT_UNSIGNED16: "@Unsigned16"
-        74 NUM_UNSIGNED16: "Unsigned16"
-        75 NUM_AT_UNSIGNED8: "@Unsigned8"
-        76 NUM_UNSIGNED8: "Unsigned8"
-        77 NUM_AT_BINARY64: "@Binary64"
-        78 NUM_BINARY64: "Binary64"
-        79 NUM_AT_BINARY32: "@Binary32"
-        80 NUM_BINARY32: "Binary32"
-        81 NUM_BITWISE_AND: "bitwiseAnd"
-        82 NUM_BITWISE_XOR: "bitwiseXor"
-        83 NUM_BITWISE_OR: "bitwiseOr"
-        84 NUM_SHIFT_LEFT: "shiftLeftBy"
-        85 NUM_SHIFT_RIGHT: "shiftRightBy"
-        86 NUM_SHIFT_RIGHT_ZERO_FILL: "shiftRightZfBy"
-        87 NUM_SUB_WRAP: "subWrap"
-        88 NUM_SUB_CHECKED: "subChecked"
-        89 NUM_SUB_SATURATED: "subSaturated"
-        90 NUM_MUL_WRAP: "mulWrap"
-        91 NUM_MUL_CHECKED: "mulChecked"
-        92 NUM_INT: "Int"
-        93 NUM_FLOAT: "Float"
-        94 NUM_AT_NATURAL: "@Natural"
-        95 NUM_NATURAL: "Natural"
-        96 NUM_NAT: "Nat"
-        97 NUM_INT_CAST: "intCast"
-        98 NUM_IS_MULTIPLE_OF: "isMultipleOf"
-        99 NUM_AT_DECIMAL: "@Decimal"
-        100 NUM_DECIMAL: "Decimal"
-        101 NUM_DEC: "Dec"   // the Num.Dectype alias
-        102 NUM_BYTES_TO_U16: "bytesToU16"
-        103 NUM_BYTES_TO_U32: "bytesToU32"
-        104 NUM_CAST_TO_NAT: "#castToNat"
-        105 NUM_DIV_CEIL: "divCeil"
-        106 NUM_TO_STR: "toStr"
-        107 NUM_MIN_I8: "minI8"
-        108 NUM_MAX_I8: "maxI8"
-        109 NUM_MIN_U8: "minU8"
-        110 NUM_MAX_U8: "maxU8"
-        111 NUM_MIN_I16: "minI16"
-        112 NUM_MAX_I16: "maxI16"
-        113 NUM_MIN_U16: "minU16"
-        114 NUM_MAX_U16: "maxU16"
-        115 NUM_MIN_I32: "minI32"
-        116 NUM_MAX_I32: "maxI32"
-        117 NUM_MIN_U32: "minU32"
-        118 NUM_MAX_U32: "maxU32"
-        119 NUM_MIN_I64: "minI64"
-        120 NUM_MAX_I64: "maxI64"
-        121 NUM_MIN_U64: "minU64"
-        122 NUM_MAX_U64: "maxU64"
-        123 NUM_MIN_I128: "minI128"
-        124 NUM_MAX_I128: "maxI128"
-        125 NUM_TO_I8: "toI8"
-        126 NUM_TO_I8_CHECKED: "toI8Checked"
-        127 NUM_TO_I16: "toI16"
-        128 NUM_TO_I16_CHECKED: "toI16Checked"
-        129 NUM_TO_I32: "toI32"
-        130 NUM_TO_I32_CHECKED: "toI32Checked"
-        131 NUM_TO_I64: "toI64"
-        132 NUM_TO_I64_CHECKED: "toI64Checked"
-        133 NUM_TO_I128: "toI128"
-        134 NUM_TO_I128_CHECKED: "toI128Checked"
-        135 NUM_TO_U8: "toU8"
-        136 NUM_TO_U8_CHECKED: "toU8Checked"
-        137 NUM_TO_U16: "toU16"
-        138 NUM_TO_U16_CHECKED: "toU16Checked"
-        139 NUM_TO_U32: "toU32"
-        140 NUM_TO_U32_CHECKED: "toU32Checked"
-        141 NUM_TO_U64: "toU64"
-        142 NUM_TO_U64_CHECKED: "toU64Checked"
-        143 NUM_TO_U128: "toU128"
-        144 NUM_TO_U128_CHECKED: "toU128Checked"
-        145 NUM_TO_NAT: "toNat"
-        146 NUM_TO_NAT_CHECKED: "toNatChecked"
-        147 NUM_TO_F32: "toF32"
-        148 NUM_TO_F32_CHECKED: "toF32Checked"
-        149 NUM_TO_F64: "toF64"
-        150 NUM_TO_F64_CHECKED: "toF64Checked"
+        39 NUM_REM_CHECKED: "remChecked"
+        40 NUM_DIV_FLOAT: "div"
+        41 NUM_DIV_FLOAT_CHECKED: "divChecked"
+        42 NUM_DIV_INT: "divFloor"
+        43 NUM_DIV_INT_CHECKED: "divFloorChecked"
+        44 NUM_MOD_INT: "modInt"
+        45 NUM_MOD_INT_CHECKED: "modIntChecked"
+        46 NUM_MOD_FLOAT: "modFloat"
+        47 NUM_MOD_FLOAT_CHECKED: "modFloatChecked"
+        48 NUM_SQRT: "sqrt"
+        49 NUM_SQRT_CHECKED: "sqrtChecked"
+        50 NUM_LOG: "log"
+        51 NUM_LOG_CHECKED: "logChecked"
+        52 NUM_ROUND: "round"
+        53 NUM_COMPARE: "compare"
+        54 NUM_POW: "pow"
+        55 NUM_CEILING: "ceiling"
+        56 NUM_POW_INT: "powInt"
+        57 NUM_FLOOR: "floor"
+        58 NUM_ADD_WRAP: "addWrap"
+        59 NUM_ADD_CHECKED: "addChecked"
+        60 NUM_ADD_SATURATED: "addSaturated"
+        61 NUM_ATAN: "atan"
+        62 NUM_ACOS: "acos"
+        63 NUM_ASIN: "asin"
+        64 NUM_AT_SIGNED128: "@Signed128"
+        65 NUM_SIGNED128: "Signed128"
+        66 NUM_AT_SIGNED64: "@Signed64"
+        67 NUM_SIGNED64: "Signed64"
+        68 NUM_AT_SIGNED32: "@Signed32"
+        69 NUM_SIGNED32: "Signed32"
+        70 NUM_AT_SIGNED16: "@Signed16"
+        71 NUM_SIGNED16: "Signed16"
+        72 NUM_AT_SIGNED8: "@Signed8"
+        73 NUM_SIGNED8: "Signed8"
+        74 NUM_AT_UNSIGNED128: "@Unsigned128"
+        75 NUM_UNSIGNED128: "Unsigned128"
+        76 NUM_AT_UNSIGNED64: "@Unsigned64"
+        77 NUM_UNSIGNED64: "Unsigned64"
+        78 NUM_AT_UNSIGNED32: "@Unsigned32"
+        79 NUM_UNSIGNED32: "Unsigned32"
+        80 NUM_AT_UNSIGNED16: "@Unsigned16"
+        81 NUM_UNSIGNED16: "Unsigned16"
+        82 NUM_AT_UNSIGNED8: "@Unsigned8"
+        83 NUM_UNSIGNED8: "Unsigned8"
+        84 NUM_AT_BINARY64: "@Binary64"
+        85 NUM_BINARY64: "Binary64"
+        86 NUM_AT_BINARY32: "@Binary32"
+        87 NUM_BINARY32: "Binary32"
+        88 NUM_BITWISE_AND: "bitwiseAnd"
+        89 NUM_BITWISE_XOR: "bitwiseXor"
+        90 NUM_BITWISE_OR: "bitwiseOr"
+        91 NUM_SHIFT_LEFT: "shiftLeftBy"
+        92 NUM_SHIFT_RIGHT: "shiftRightBy"
+        93 NUM_SHIFT_RIGHT_ZERO_FILL: "shiftRightZfBy"
+        94 NUM_SUB_WRAP: "subWrap"
+        95 NUM_SUB_CHECKED: "subChecked"
+        96 NUM_SUB_SATURATED: "subSaturated"
+        97 NUM_MUL_WRAP: "mulWrap"
+        98 NUM_MUL_CHECKED: "mulChecked"
+        99 NUM_INT: "Int"
+        100 NUM_FLOAT: "Float"
+        101 NUM_AT_NATURAL: "@Natural"
+        102 NUM_NATURAL: "Natural"
+        103 NUM_NAT: "Nat"
+        104 NUM_INT_CAST: "intCast"
+        105 NUM_IS_MULTIPLE_OF: "isMultipleOf"
+        106 NUM_AT_DECIMAL: "@Decimal"
+        107 NUM_DECIMAL: "Decimal"
+        108 NUM_DEC: "Dec"  // the Num.Dectype alias
+        109 NUM_BYTES_TO_U16: "bytesToU16"
+        110 NUM_BYTES_TO_U32: "bytesToU32"
+        111 NUM_CAST_TO_NAT: "#castToNat"
+        112 NUM_DIV_CEIL: "divCeil"
+        113 NUM_DIV_CEIL_CHECKED: "divCeilChecked"
+        114 NUM_TO_STR: "toStr"
+        115 NUM_MIN_I8: "minI8"
+        116 NUM_MAX_I8: "maxI8"
+        117 NUM_MIN_U8: "minU8"
+        118 NUM_MAX_U8: "maxU8"
+        119 NUM_MIN_I16: "minI16"
+        120 NUM_MAX_I16: "maxI16"
+        121 NUM_MIN_U16: "minU16"
+        122 NUM_MAX_U16: "maxU16"
+        123 NUM_MIN_I32: "minI32"
+        124 NUM_MAX_I32: "maxI32"
+        125 NUM_MIN_U32: "minU32"
+        126 NUM_MAX_U32: "maxU32"
+        127 NUM_MIN_I64: "minI64"
+        128 NUM_MAX_I64: "maxI64"
+        129 NUM_MIN_U64: "minU64"
+        130 NUM_MAX_U64: "maxU64"
+        131 NUM_MIN_I128: "minI128"
+        132 NUM_MAX_I128: "maxI128"
+        133 NUM_TO_I8: "toI8"
+        134 NUM_TO_I8_CHECKED: "toI8Checked"
+        135 NUM_TO_I16: "toI16"
+        136 NUM_TO_I16_CHECKED: "toI16Checked"
+        137 NUM_TO_I32: "toI32"
+        138 NUM_TO_I32_CHECKED: "toI32Checked"
+        139 NUM_TO_I64: "toI64"
+        140 NUM_TO_I64_CHECKED: "toI64Checked"
+        141 NUM_TO_I128: "toI128"
+        142 NUM_TO_I128_CHECKED: "toI128Checked"
+        143 NUM_TO_U8: "toU8"
+        144 NUM_TO_U8_CHECKED: "toU8Checked"
+        145 NUM_TO_U16: "toU16"
+        146 NUM_TO_U16_CHECKED: "toU16Checked"
+        147 NUM_TO_U32: "toU32"
+        148 NUM_TO_U32_CHECKED: "toU32Checked"
+        149 NUM_TO_U64: "toU64"
+        150 NUM_TO_U64_CHECKED: "toU64Checked"
+        151 NUM_TO_U128: "toU128"
+        152 NUM_TO_U128_CHECKED: "toU128Checked"
+        153 NUM_TO_NAT: "toNat"
+        154 NUM_TO_NAT_CHECKED: "toNatChecked"
+        155 NUM_TO_F32: "toF32"
+        156 NUM_TO_F32_CHECKED: "toF32Checked"
+        157 NUM_TO_F64: "toF64"
+        158 NUM_TO_F64_CHECKED: "toF64Checked"
     }
     2 BOOL: "Bool" => {
         0 BOOL_BOOL: "Bool" // the Bool.Bool type alias
diff --git a/compiler/solve/tests/solve_expr.rs b/compiler/solve/tests/solve_expr.rs
index 9a4257d2f6..98acd4ca96 100644
--- a/compiler/solve/tests/solve_expr.rs
+++ b/compiler/solve/tests/solve_expr.rs
@@ -3300,6 +3300,30 @@ mod solve_expr {
         );
     }
 
+    #[test]
+    fn div() {
+        infer_eq_without_problem(
+            indoc!(
+                r#"
+                Num.div
+                "#
+            ),
+            "Float a, Float a -> Float a",
+        )
+    }
+
+    #[test]
+    fn div_checked() {
+        infer_eq_without_problem(
+            indoc!(
+                r#"
+                Num.divChecked
+                "#
+            ),
+            "Float a, Float a -> Result (Float a) [ DivByZero ]*",
+        )
+    }
+
     #[test]
     fn div_ceil() {
         infer_eq_without_problem(
@@ -3308,22 +3332,46 @@ mod solve_expr {
                 Num.divCeil
                 "#
             ),
+            "Int a, Int a -> Int a",
+        );
+    }
+
+    #[test]
+    fn div_ceil_checked() {
+        infer_eq_without_problem(
+            indoc!(
+                r#"
+                Num.divCeilChecked
+                "#
+            ),
             "Int a, Int a -> Result (Int a) [ DivByZero ]*",
         );
     }
 
     #[test]
-    fn pow_int() {
+    fn div_floor() {
         infer_eq_without_problem(
             indoc!(
                 r#"
-                Num.powInt
+                Num.divFloor
                 "#
             ),
             "Int a, Int a -> Int a",
         );
     }
 
+    #[test]
+    fn div_floor_checked() {
+        infer_eq_without_problem(
+            indoc!(
+                r#"
+                Num.divFloorChecked
+                "#
+            ),
+            "Int a, Int a -> Result (Int a) [ DivByZero ]*",
+        );
+    }
+
     #[test]
     fn atan() {
         infer_eq_without_problem(
diff --git a/compiler/test_gen/src/gen_num.rs b/compiler/test_gen/src/gen_num.rs
index d7cc51c396..a456dbd40c 100644
--- a/compiler/test_gen/src/gen_num.rs
+++ b/compiler/test_gen/src/gen_num.rs
@@ -723,11 +723,24 @@ fn gen_wrap_add_nums() {
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
 fn gen_div_f64() {
-    // FIXME this works with normal types, but fails when checking uniqueness types
     assert_evals_to!(
         indoc!(
             r#"
-                    when 48 / 2 is
+                    48 / 2
+                "#
+        ),
+        24.0,
+        f64
+    );
+}
+
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn gen_div_checked_f64() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+                    when Num.divChecked 48 2 is
                         Ok val -> val
                         Err _ -> -1
                 "#
@@ -736,6 +749,23 @@ fn gen_div_f64() {
         f64
     );
 }
+
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn gen_div_checked_by_zero_f64() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+                    when Num.divChecked 47 0 is
+                        Ok val -> val
+                        Err _ -> -1
+                "#
+        ),
+        -1.0,
+        f64
+    );
+}
+
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
 fn gen_div_dec() {
@@ -748,7 +778,27 @@ fn gen_div_dec() {
                     y : Dec
                     y = 3
 
-                    when x / y is
+                    x / y
+                "#
+        ),
+        RocDec::from_str_to_i128_unsafe("3.333333333333333333"),
+        i128
+    );
+}
+
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn gen_div_checked_dec() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+                    x : Dec
+                    x = 10
+
+                    y : Dec
+                    y = 3
+
+                    when Num.divChecked x y is
                         Ok val -> val
                         Err _ -> -1
                 "#
@@ -757,6 +807,27 @@ fn gen_div_dec() {
         i128
     );
 }
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn gen_div_checked_by_zero_dec() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+                    x : Dec
+                    x = 10
+
+                    y : Dec
+                    y = 0
+
+                    when Num.divChecked x y is
+                        Ok val -> val
+                        Err _ -> -1
+                "#
+        ),
+        RocDec::from_str_to_i128_unsafe("-1"),
+        i128
+    );
+}
 
 #[test]
 #[cfg(any(feature = "gen-llvm", feature = "gen-dev", feature = "gen-wasm"))]
@@ -965,7 +1036,21 @@ fn gen_div_i64() {
     assert_evals_to!(
         indoc!(
             r#"
-                    when 1000 // 10 is
+                    1000 // 10
+                "#
+        ),
+        100,
+        i64
+    );
+}
+
+#[test]
+#[cfg(any(feature = "gen-llvm"))]
+fn gen_div_checked_i64() {
+    assert_evals_to!(
+        indoc!(
+            r#"
+                    when Num.divFloorChecked 1000 10 is
                         Ok val -> val
                         Err _ -> -1
                 "#
@@ -977,11 +1062,11 @@ fn gen_div_i64() {
 
 #[test]
 #[cfg(any(feature = "gen-llvm"))]
-fn gen_div_by_zero_i64() {
+fn gen_div_checked_by_zero_i64() {
     assert_evals_to!(
         indoc!(
             r#"
-                    when 1000 // 0 is
+                    when Num.divFloorChecked 1000 0 is
                         Err DivByZero -> 99
                         _ -> -24
                 "#
diff --git a/compiler/test_mono/src/tests.rs b/compiler/test_mono/src/tests.rs
index ff9b7bfcaa..777a790d52 100644
--- a/compiler/test_mono/src/tests.rs
+++ b/compiler/test_mono/src/tests.rs
@@ -274,7 +274,7 @@ fn ir_round() {
 #[mono_test]
 fn ir_when_idiv() {
     r#"
-    when 1000 // 10 is
+    when Num.divFloorChecked 1000 10 is
         Ok val -> val
         Err _ -> -1
     "#
diff --git a/examples/benchmarks/Deriv.roc b/examples/benchmarks/Deriv.roc
index 2cad781765..caf08906a6 100644
--- a/examples/benchmarks/Deriv.roc
+++ b/examples/benchmarks/Deriv.roc
@@ -42,7 +42,7 @@ Expr : [ Val I64, Var Str, Add Expr Expr, Mul Expr Expr, Pow Expr Expr, Ln Expr
 divmod : I64, I64 -> Result { div : I64, mod : I64 } [ DivByZero ]*
 divmod = \l, r ->
     when Pair (l // r) (l % r) is
-        Pair (Ok div) (Ok mod) ->
+        Pair div (Ok mod) ->
             Ok { div, mod }
 
         _ ->
diff --git a/examples/benchmarks/RBTreeDel.roc b/examples/benchmarks/RBTreeDel.roc
index 24419ef84a..43fd309e5d 100644
--- a/examples/benchmarks/RBTreeDel.roc
+++ b/examples/benchmarks/RBTreeDel.roc
@@ -47,7 +47,7 @@ makeMapHelp = \total, n, m ->
             isFrequency =
                 n |> Num.isMultipleOf 4
 
-            key = n1 + ((total - n1) // 5 |> resultWithDefault 0)
+            key = n1 + ((total - n1) // 5)
             t2 = if isFrequency then delete t1 key else t1
 
             makeMapHelp total n1 t2
diff --git a/examples/false-interpreter/False.roc b/examples/false-interpreter/False.roc
index d7e0ac0c4f..f8306e7d8d 100644
--- a/examples/false-interpreter/False.roc
+++ b/examples/false-interpreter/False.roc
@@ -434,7 +434,7 @@ stepExecCtx = \ctx, char ->
                 (
                     (T popCtx1 numR) <- Result.after (popNumber ctx)
                     (T popCtx2 numL) <- Result.after (popNumber popCtx1)
-                    res <- Result.after (Num.divFloor numL numR)
+                    res <- Result.after (Num.divFloorChecked numL numR)
                     Ok (Context.pushStack popCtx2 (Number res))
                 )
 
diff --git a/examples/gui/Hello.roc b/examples/gui/Hello.roc
index c15f5bd21a..653ccbd8e1 100644
--- a/examples/gui/Hello.roc
+++ b/examples/gui/Hello.roc
@@ -4,9 +4,7 @@ app "hello-gui"
     provides [ render ] to pf
 
 render =
-    div0 = \numerator, denominator -> (numerator / denominator) |> Result.withDefault 0
-
-    rgba = \r, g, b, a -> { r: div0 r 255, g: div0 g 255, b: div0 b 255, a }
+    rgba = \r, g, b, a -> { r: r / 255, g: g / 255, b: b / 255, a }
 
     styles = { bgColor: rgba 100 50 50 1, borderColor: rgba 10 20 30 1, borderWidth: 10, textColor: rgba 220 220 250 1 }
 
diff --git a/repl_test/src/tests.rs b/repl_test/src/tests.rs
index 884c752cde..0d1aba07a2 100644
--- a/repl_test/src/tests.rs
+++ b/repl_test/src/tests.rs
@@ -61,23 +61,41 @@ fn num_rem() {
 
 #[cfg(not(feature = "wasm"))]
 #[test]
-fn num_floor_division_success() {
-    expect_success("Num.divFloor 4 3", "Ok 1 : Result (Int *) [ DivByZero ]*");
+fn num_floor_division() {
+    expect_success("Num.divFloor 4 3", "1 : Int *");
 }
 
 #[cfg(not(feature = "wasm"))]
 #[test]
-fn num_floor_division_divby_zero() {
+fn num_floor_checked_division_success() {
     expect_success(
-        "Num.divFloor 4 0",
+        "Num.divFloorChecked 4 3",
+        "Ok 1 : Result (Int *) [ DivByZero ]*",
+    );
+}
+
+#[cfg(not(feature = "wasm"))]
+#[test]
+fn num_floor_checked_division_divby_zero() {
+    expect_success(
+        "Num.divFloorChecked 4 0",
         "Err DivByZero : Result (Int *) [ DivByZero ]*",
     );
 }
 
 #[cfg(not(feature = "wasm"))]
 #[test]
-fn num_ceil_division_success() {
-    expect_success("Num.divCeil 4 3", "Ok 2 : Result (Int *) [ DivByZero ]*")
+fn num_ceil_division() {
+    expect_success("Num.divCeil 4 3", "2 : Int *")
+}
+
+#[cfg(not(feature = "wasm"))]
+#[test]
+fn num_ceil_checked_division_success() {
+    expect_success(
+        "Num.divCeilChecked 4 3",
+        "Ok 2 : Result (Int *) [ DivByZero ]*",
+    )
 }
 
 #[test]