4 、There is a number, when divided by 3 the remainder is 1, when divided by 5 the remainder is 2, so what is the remainder when this number is divided by 15?
【Analysis】Let this number be $3k+1$. If $(3k+1)$ divided by 5 leaves a remainder of 2, then the smallest value of $k$ is 2, so the smallest value of this number is 7.