diff --git a/eBook/10.7.md b/eBook/10.7.md
index 57bf14c..82bba86 100644
--- a/eBook/10.7.md
+++ b/eBook/10.7.md
@@ -51,7 +51,7 @@ func (tn *TwoInts) String() string {
 type TT float64
 
 func (t TT) String() string {
-    return fmt.Sprintf("%v", s)
+    return fmt.Sprintf("%v", t)
 }
 t. String()
 ```