Question

(a) How could you calculate 23 x 4 on your calculator if the 4 button is broken? (b) How could you calculate 23 x 21 if the 2 button on your calculator is broken?

Answer 1

Answer:

23 x 4

=> 23 x (2 + 2)

=> 23 x 2 + 23 x 2

23 x 21

=> 23 x (3 x 7)

=> (23 x 3) x (23 x 7)