1 files changed, 7 insertions, 0 deletions
diff --git a/web/src/math/Ratio.ts b/web/src/math/Ratio.ts
index d8e1149..0cca966 100644
--- a/web/src/math/Ratio.ts
+++ b/web/src/math/Ratio.ts
@@ -50,6 +50,13 @@ export default class Ratio {
     );
   }
 
+  subtract(other: Ratio): Ratio {
+    return new Ratio(
+      this.numerator * other.denominator - other.numerator * this.denominator,
+      this.denominator * other.denominator,
+    );
+  }
+
   compare(other: Ratio): number {
     const left = this.numerator * other.denominator;
     const right = other.numerator * this.denominator;