Question

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

Answer 1

So all you have to do is take the first numbers of each multiple and multiply them.
1 x 2 x 3 x 4 = 24
Now you just add the 4 zeros to your answer.
240,000

Our answer even checks!
10 x 20 x 30 x 40 = 240,000

Good Luck! :)