Math question: Can the difference between three digits, hundred digits and single digits be divisible by 99? Tell me your reasons.
Let one hundred digits be a, ten digits be b and one digit be c, (100a+10b+c)-(100c+10b+a).
= 100a-a+c- 100c
=99a-99c
=99 (AC)
So the difference can be divisible by 99.