What number goes into 40 70 and 84?

Answer 1

In looking into this question, I believe that one must know the "greatest common factor" between the three. The answer would be "two" - they are all even numbers, and two is the greatest common number between them. Any higher and you get some that factor into one, but not the other (e.g. "four" would work with 40 and 84, but not 70; "seven" would work with 70 and 84 but not 40, and so on).

I hope this helps!