diff --git a/README.md b/README.md
index 325f2e6..2db5c7a 100644
--- a/README.md
+++ b/README.md
@@ -23,3 +23,4 @@
 96 - 21 = 75
 32 - 80 = -48
 44 / 10 = 4
+80 - 80 = 0