diff --git a/shell/fibonacci.sh b/shell/fibonacci.sh
index 88532d3..3626ea6 100755
--- a/shell/fibonacci.sh
+++ b/shell/fibonacci.sh
@@ -7,7 +7,7 @@ fibonacci() {
 		return 0
 	fi
 
-	(tee /dev/stderr | tail -n 2 | awk '{s += $1} END {print s}') 2>&1 | fibonacci $((i - 1))
+	(tee /dev/stderr | tail -n 2 | paste -s -d "+" | bc) 2>&1 | fibonacci $((i - 1))
 }
 
 fibonacci 5 <<EOF