diff --git a/comma.go b/comma.go
index 9d0d2ed..80dbfa7 100644
--- a/comma.go
+++ b/comma.go
@@ -33,7 +33,7 @@
 		j--
 	}
 	parts[j] = strconv.Itoa(int(v))
-	return sign + strings.Join(parts[j:len(parts)], ",")
+	return sign + strings.Join(parts[j:], ",")
 }
 
 // Commaf produces a string form of the given number in base 10 with
@@ -97,5 +97,5 @@
 		j--
 	}
 	parts[j] = strconv.Itoa(int(b.Int64()))
-	return sign + strings.Join(parts[j:len(parts)], ",")
+	return sign + strings.Join(parts[j:], ",")
 }