This is the changing law of elements and products.

First of all, look at the following two groups of questions, and carefully observe the changing law of factor and product in the two groups of formulas. Through observation, the most obvious feature of the two groups of formulas is that one of the factors has not changed.

For example, the first factor of the first group is always 6 and the second factor of the second group is always 4. Let's look at it separately.

In the first group, one factor did not change, while the other factor showed an expanding trend. From the first formula to the second formula, 2 to 20 expands 10 times (multiplied by 10), and the product also expands 10 times (multiplied by 10).

The second formula to the third formula, from 20 to 80, is expanded by 4 times (multiplied by 4) and the product is also expanded by 4 times (multiplied by 4). So we can draw a conclusion that if a factor is constant, then the product will be multiplied several times.

Extended data:

It should be noted that this relationship only holds if the dividend, divisor and quotient are integers and the remainder is zero. On the contrary, we call c a multiple of a and b, and we don't consider 0 when studying factors and multiples.

In primary school mathematics, two positive integers are multiplied, so both numbers are called factors of product, or divisors.

In fact, factors are generally defined as integers: let a be an integer and b be a non-zero integer. If there is an integer Q that makes A=QB, then B is a factor of A, denoted as B | A ... but some authors do not require B≠0.