In the calculator challenge, one of the user stories is:

User Story: I can keep chaining mathematical operations together until I hit the equal button, and the calculator will tell me the correct output.

Is it ok if the calculator evaluates after every step instead?

So instead of 2 + 3 + 4 = 9, it would be 2 + 3 gets evaluated to 5 first, and then 5 + 4 would evaluate to 9.