diff --git a/src/util.rs b/src/util.rs
new file mode 100644
index 0000000..d5cb60d
--- /dev/null
+++ b/src/util.rs
@@ -0,0 +1,15 @@
+
+pub fn gcd(a: usize, b: usize) -> usize {
+	if a == 0 || b == 0 { return 0; }
+	let min = usize::min(a, b);
+	let max = usize::max(a, b);
+
+	let remainder = max % min;
+	if remainder == 0 { return min; }
+	else { return gcd(min, remainder); }
+}
+
+pub fn lcm(a: usize, b: usize) -> usize {
+	return ( a * b ) / gcd(a, b);
+}
+