Warm-up

Simplify the following expression:

(√2+√3+√5)(√2+√3-√5)(√2-√3+√5)(-√2+√3+√5)

[Your answer should be an integer]

The challenge

Replace each __ in the following expression with + or - so that the expression simplifies to give an integer. You should be able to do it without a calculator!

(√2__√3__√5__√7)(√2__√3__√5__√7)(√2__√3__√5__√7)(√2__√3__√5__√7)(√2__√3__√5__√7)(√2__√3__√5__√7)(√2__√3__√5__√7)(√2__√3__√5__√7)

[If it's too big for your screen, you should see eight of the same bracket multiplied together]