What is cuberoot(64x1000)?

This is a question from a non calculator GCSE paper only answered correctly by roughly half the students. The question is regarding the topic of surds and is quite a basic question testing your knowledge on the laws of surds. The important thing to know is the rule that sqrt(a) x sqrt(b) = sqrt(a x b) and that the same applies to a cube root and any other root.
Using that information this question becomes relatively easy. Cuberoot(64x1000) can be split into cuberoot(64) x cuberoot(1000). Cuberoot(64) is 4 (this can be found in an exam by either knowing it or by trial and error) and cuberoot(1000) is 10. Therefore the answer is just 4 x 10 which is 40.