13. What is the remainder when $12345 \times 54321$ is divided by 9 ?
A 0
B 1
С 2
D 3
E 4
13. A Note that the sum of the digits of 12345 is 15 . So 12345 is a multiple of 3 .
Similarly, 54321 is a multiple of 3 . Therefore the product of these two integers is a multiple of 9 . Hence the remainder when $12345 \times 54321$ is divided by 9 is 0 .