Thanks for the feedback is much appreciated.
In the original design, in my head, I was going to randomise the order and number of operations, so when designing the game, I started with an equation that was easy to test the concept. If I get time to update, will it have an easy, medium and hard mode, with easy being "? +? = r", then increase the difficulty equation with each completed round.
Colliders are interesting, and I had already made the ship's collider smaller than the ship because it was too easy to clip bolts and numbers from the side when the ship was moving.