diff --git a/lib/function/arithmetic/lcm.js b/lib/function/arithmetic/lcm.js
index f51a4b384..874a48226 100644
--- a/lib/function/arithmetic/lcm.js
+++ b/lib/function/arithmetic/lcm.js
@@ -46,7 +46,9 @@ function factory (type, config, load, typed) {
 
     'BigNumber, BigNumber': _lcmBigNumber,
 
-    // TODO: implement support for Fraction
+    'Fraction, Fraction': function (x, y) {
+      return x.mul(y).abs().div(x.gcd(y));
+    },
 
     'Matrix, Matrix': function (x, y) {
       // result