diff --git a/libcst/nodes/tests/test_number.py b/libcst/nodes/tests/test_number.py
index 67be699b..ca611c68 100644
--- a/libcst/nodes/tests/test_number.py
+++ b/libcst/nodes/tests/test_number.py
@@ -61,7 +61,34 @@ class NumberTest(CSTNodeTest):
                 parse_expression,
                 CodeRange.create((1, 0), (1, 3)),
             ),
-            # TODO: add test cases for "((5))" and "(+((5)))"
+            # multiple nested parenthesis
+            (
+                cst.Number(
+                    cst.Integer(
+                        "5",
+                        lpar=(cst.LeftParen(), cst.LeftParen()),
+                        rpar=(cst.RightParen(), cst.RightParen()),
+                    )
+                ),
+                "((5))",
+                parse_expression,
+                CodeRange.create((1, 0), (1, 5)),
+            ),
+            (
+                cst.Number(
+                    lpar=(cst.LeftParen(),),
+                    operator=cst.Plus(),
+                    number=cst.Integer(
+                        "5",
+                        lpar=(cst.LeftParen(), cst.LeftParen()),
+                        rpar=(cst.RightParen(), cst.RightParen()),
+                    ),
+                    rpar=(cst.RightParen(),),
+                ),
+                "(+((5)))",
+                parse_expression,
+                CodeRange.create((1, 1), (1, 7)),
+            ),
         )
     )
     def test_valid(
diff --git a/libcst/parser/_conversions/expression.py b/libcst/parser/_conversions/expression.py
index fde47282..19c1bba4 100644
--- a/libcst/parser/_conversions/expression.py
+++ b/libcst/parser/_conversions/expression.py
@@ -790,7 +790,8 @@ def convert_atom_parens(config: ParserConfig, children: Sequence[Any]) -> Any:
             return WithLeadingWhitespace(
                 inner_atom.with_changes(
                     number=inner_atom.number.with_changes(
-                        lpar=(lpar, *inner_atom.lpar), rpar=(*inner_atom.rpar, rpar)
+                        lpar=(lpar, *inner_atom.number.lpar),
+                        rpar=(*inner_atom.number.rpar, rpar),
                     )
                 ),
                 lpar_tok.whitespace_before,