Find the digit that makes _2‚530 divisible by 9.
read up on "casting out nines"
If the missing digit is x, we need
x+2+5+3+0 = x+10
to be a multiple of 9. The smallest such which is bigger than 10 is 18, so x = 8, and the number is 82530 = 9*9170
If the missing digit is x, we need
x+2+5+3+0 = x+10
to be a multiple of 9. The smallest such which is bigger than 10 is 18, so x = 8, and the number is 82530 = 9*9170