Question

cmr:

abc-cba chia het cho 99

Answer 1

abc - cba = (100a + 10b + c) - (100c + 10b + a) = 100a + 10b + c - 100c - 10b - a = 99a - 99c = 99(a - c) luôn chia hết cho 99

Vậy abc - cba chia hết cho 99

Answer 2

abc-cba=(100a+10b+c)-(100c+10b+a)=99a-99b