A cookie recipe calls for one-third of a cup of peanutbutter. How much peanut butter is needed to make one-fourth of the recipe?

Question

I need help decidering this problem. What do I do with the numbers?

Answer 1

You need to multiply the numbers. Imagine the recipe in a cup. Cut the cup in 4 equal pieces. Each one will contain 1/4 of the matter. This is why you need to multiply.

 

It is the same logic, as you need to double, triple quadruple, etc. You multiply by 2, 3, 4, ... the amount of the recipe.