Edit: Sorry, I just noticed that actually I was missing the point - I thought your comment was in response to vacri. Leaving my comment here, just in case. I t

Edit: Sorry, I just noticed that actually I was missing the point - I thought your comment was in response to vacri. Leaving my comment here, just in case. I think your comment misses the point. It's important to learn when to use a calculator and when to simplify the equation instead. Your example obviously should be simplified first on paper, resulting in 2. This can easily be enforced by requiring the intermediate steps, such that a calculator won't work. The point of parent is, that learning pen-and-paper calculation is of basically no value (except if you go into computer science, where remembering those algorithms can come in handy). Your example is not calculation, it's arithmetics, a necessary step towards algebra.