I have a question on a very basic operation of modulo operator. Why does 1 % 9 produce 1? If 10 % 9 then remainder is 1.

I am very poor in math but have had to use modulo operator
many times before but always become confused and couldn't
understand the logic when dividend is smaller than divisor.

This is a fingerprint verification application. When verifying,it loops through the table. if the current fingerprint template is the first one on the table row it verifies it correctly. But ...