Well when you do a problem and it's multiplication and you have to us your math skills and then when you get it wrong don't that mean that it do not work and you need to us another skill to answer your question.

Not necessarily. You could have done your multiplication wrong. Or in some cases, yes, you could have to use another skill. For example, you can't solve an optimization problem with addition, you need some calculus skills under your belt.

Ithink the answer is last one.