Question

Write three four-digit numbers that are divisible by 4,5, and 9.

Answer 1

4500, 1000, and 1005

Answer 2

To be divisible by 5, the last digit needs to be 5 or 0.

To be divisible by 4 as well, your number will need to end with 20, 40, 60, 80, or 00.

To be divisible by 9, the digits need to add up to 9, 18, 27, 36, etc.

So, ending with 20, 6120 works, as does 5220, 4320, 3420, 2520, and 1620.

If we move the ending with 40, 1440 works, as does 2340, 3240, 4140, 5940, and 6840.