diff --git a/jiyunpar/math/6064.cpp b/jiyunpar/math/6064.cpp
new file mode 100644
index 0000000..32e9a71
--- /dev/null
+++ b/jiyunpar/math/6064.cpp
@@ -0,0 +1,46 @@
+#include <iostream>
+
+using namespace std;
+
+int	gcd(int a, int b)
+{
+	if (b == 0)
+		return (a);
+	return (gcd(b, a % b));
+}
+
+int lcm(int a, int b)
+{
+	return (a / gcd(a, b) * b);
+}
+
+int solved(int m, int n, int x, int y)
+{
+	if (x == m)
+		x = 0;
+	if (y == n)
+		y = 0;
+	int l = lcm(m, n);
+	for (int i = x; i <= l; i += m)
+	{
+		if (i == 0)
+			continue;
+		if (i % n == y)
+			return (i);
+	}
+	return (-1);
+}
+
+int main(void)
+{
+	ios::sync_with_stdio(0);
+	cin.tie(0);
+	int t, n, m, x, y;
+	cin >> t;
+	for (int i = 0; i < t; ++i)
+	{
+		cin >> m >> n >> x >> y;
+		cout << solved(m, n, x, y) << '\n';
+	}
+	return (0);
+}
\ No newline at end of file
diff --git a/jiyunpar/math/gcd.cpp b/jiyunpar/math/gcd.cpp
new file mode 100644
index 0000000..8eef934
--- /dev/null
+++ b/jiyunpar/math/gcd.cpp
@@ -0,0 +1,25 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+int	gcd(int a, int b)
+{
+	if (b == 0)
+		return (a);
+	return (gcd(b, a % b));
+}
+
+int lcm(int a, int b)
+{
+	return (a / gcd(a, b) * b);
+}
+
+int main(void)
+{
+	int a, b, ans;
+	cin >> a >> b;
+	ans = lcm(a, b);
+	cout << ans;
+	return (0);
+}
\ No newline at end of file