Question

A.) Multiply these numbers the quickest and easiest way possible: 87 x 5 x 2 B.) Explain how you were able to quickly determine the product. Justify your reasoning using a property of multiplication.

Answer 1

It is easy to multiply numbers by 10: you simply have to add an extra zero at the end.

This means that, using associative property, we know that

87 x 5 x 2=(87 x 5) x 2=87 x (5 x 2)

The last expression is the easiest to compute, because we have

87 x (5 x 2) = 87 x 10 = 870

Hope I helped.