Xiao Wang goes to the library every three days, and Xiao Zhang goes to the library every five days. If one day they go to the library at the same time, how many days will they be together again at lea

Xiao Wang goes to the library every three days, and Xiao Zhang goes to the library every five days. If one day they go to the library at the same time, the problem is to find the least common multiple.

Formula: 3x5= 15.

Multiplication:

(1) How much is it?

(2) How many times is a number;

③ Find the area and volume of the object;

(4) Find the fraction or percentage of a number.

Department:

(1) divide a number into several parts on average and find one of them;

(2) How many other numbers are there in a number;

(3) What fraction or percentage of a number is known to find this number;

(4) Find a number that is several times that of another number.

Xiao Fang went to the library and borrowed the book "100,000 Why". When he took it home, he found that several pages had been torn off. If he doesn't repair them, he may fall down and become disabled.