My family have one dog,her name is Anna.She so cute and she like play a ball.My father so love her,because she is a clever's dog.Anna like meat and sandwich,in morning my mom cook for her a interesting's sandwich.I love my dog because went i go home she run back to me and said:''GAU GAU.''My dog is my best friend.

c.điệp từ

bằng 1

bằng 3

vì 2 chia hết cho a và 3 cũng chia hết a nên tổng của nó cũng chia hết cho a