How to ask a simple maths / arithmetic question
The method is correct, but the word should be '几' , not '什么'. If you ask 等于什么? it will 等于数字 ever, brain-teaser :)

几 is used more when you calculate simple questions, can be replaced with 多少 which is a common word.

七乘以六等于几?
七乘以六等于多少?

12345乘以4545等于几?(acceptable, but 多少 is more appropriate due to the complexity).


you can cut the 以, there's no difference in practice.