What number do you get when you multiply all of the numbers on a telephone's number pad?
0
Anything multiplied by 0 will equal 0.
Why this works
This riddle is clever because it plays on our expectations about multiplication and the numbers involved. When you think of the numbers on a telephone's number pad—1 through 9 and 0—most people might focus on the other digits. However, the presence of 0 is key, as multiplying any number by 0 results in 0. Therefore, regardless of the other numbers, the answer is always 0!