The four-digit number “25AB” is divisible by nine, with A the tens digit and B the units digit. How many different such four-digit numbers could “25AB” represent?

Guest Nov 3, 2019

#1**+1 **

The four-digit number “25AB” is divisible by nine, with A the tens digit and B the units digit. How many different such four-digit numbers could “25AB” represent?

Well,

The four digits must add to a number that is divisable by 9.

A+B can be no more than 18

2+5=7

A+B+7 can be no more than 25

so

A+B+7=9 or 18

You can finish it.

Melody Nov 3, 2019