Add mixed operation with + - * /

test.bats

@@ -66,3 +66,8 @@
 	[ "$result" = "4" ]
 }
 
+@test "Mixed operation with * + / -" {
+	result="$(echo '15 * (1 + 1 + 1 + 4 - 2*2) / 3 / 15 =' | ./eval.out)"
+	[ "$result" = "1" ]
+}
+