diff --git a/src/github.sh b/src/github.sh
index 09f92af..c96abd7 100644
--- a/src/github.sh
+++ b/src/github.sh
@@ -40,10 +40,10 @@ github::calculate_total_modifications() {
         add=$(_jq '.additions')
         del=$(_jq '.deletions')
 
-        ((additions += add))
+        additions=$((additions + add))
 
         if [ "$ignore_file_deletions" != "true" ]; then
-          ((deletions += del))
+          deletions=$((deletions + del))
         fi
       fi
     done