diff --git a/aoc_cas/aoc2024/day3.py b/aoc_cas/aoc2024/day3.py
new file mode 100644
index 0000000..5a9b07e
--- /dev/null
+++ b/aoc_cas/aoc2024/day3.py
@@ -0,0 +1,29 @@
+import re
+
+from aoc_cas.cli import solve
+
+MUL_REGEX = re.compile(r"mul\((\d+,\d+)\)")
+DO_DONT_REGEX = re.compile(r"((don't\(\)).+?(do\(\)))|don't\(\).+?$")
+
+
+def _sum_mults(data: str) -> int:
+    result = 0
+    for match in MUL_REGEX.findall(data):
+        n1, n2 = map(int, match.split(","))
+        result += n1 * n2
+    return result
+
+
+def part_a(data: str) -> int:
+    return _sum_mults(data)
+
+
+def part_b(data: str) -> int:
+    donts_removed = DO_DONT_REGEX.sub("", data.replace("\n", ""))
+    return _sum_mults(donts_removed)
+
+
+if __name__ == "__main__":
+    from aoc_cas.util import solve_with_examples
+
+    solve_with_examples(year=2024, day=3)
diff --git a/tests/fixtures/2024/3.txt b/tests/fixtures/2024/3.txt
new file mode 100644
index 0000000..a267c8b
--- /dev/null
+++ b/tests/fixtures/2024/3.txt
@@ -0,0 +1,8 @@
+xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))
+mul
+-
+161
+===
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))
+-
+48
\ No newline at end of file