Question

Explain how using basic facts can help you find 10 X 20 X 30 X 40 mentally?

Answer 1

Take the left side of each number first. Do 1 x 2 x 3 x 4. That equals 24. Easy. Now, count the 0's in the equation which are 4 of them. Add the four zeros and to the 24 and that's your answer. 240,000

Answer 2

First you o 10*20 which is 200. Then multiply it by 30 that equals to 6000. And then multiply it by 40 that is 240,000.