The approximate number of primary school size should be small at the same time, taking decimals. For example, the divisor of 3 and 6 is 3, and both numbers can be divisible by 3, so the divisor of these two numbers is 3, but the common divisor of these two numbers needs to be large, and the common divisor of 3 and 6 is 12, so 3 and 6 can be divisible. To sum up, the size divisor is about small at the same time.