What do 10, 25, 50, and 125 have in common

They are all divisible by 5, in other words, they are all multiples of 5

All of those numbers are . . .

-- real numbers
-- rational numbers
-- integers
-- natural numbers
-- positive numbers
-- equal to or greater than 10
-- equal to or less than 125
-- multiples of  5
-- factors of  250  and of all its multiples

Letter a i would say