Just replace the data casually for this kind of problem.

Arithmetic progression's conclusion is that the sum of two positive numbers is equal, so the closer the two numbers are to the middle value, the greater the product.

Geometric series. . . . . . The product of two positive numbers is equal, so the closer to the square value, the smaller the sum of the two numbers;

If you have to solve the problem. . .

1, let the sum of two numbers be a, the product of two numbers be y, and one number be x, then y=x(a-x). It becomes a quadratic function problem. Therefore, on the left side of the symmetry axis x=a/2, the product A3(A7) corresponding to the smaller X will be smaller than A4(A6).

2. Let the product of two numbers be k (obviously here, k >；; 0), the sum of two numbers is y, where a certain number x represents y=x+k/x, which is a check function.

Therefore, to the left of checkpoint x=B6, the smaller number B4(B8) will have a y value greater than B5(B7).