2×6= 3×8= 7×5= 8×6= 4×5= 7×3= 9×4=

5×5= 8×3= 3×6= 7×4= 9×5= 2×5= 6×9=

7×7= 5×3= 4×8= 2× 1= 8×8= 6×7= 7×2=

4×7= 9×3= 1×5= 2×8= 5×7= 4×2= 7×3=

9×8= 5×3= 4× 1= 5×6= 2×7= 2×2= 5×5=

meaning

3×5 means the addition of five 3s.

5x3 represents the addition of three 5s.

If there is a direct ratio between the dependent variable f and the independent variable X 1, X2, X3, ... Xn are qualitatively different from each independent variable, without any independent variable f, it will lose its meaning, which is called multiplication.

In probability theory, the result of an event needs to be divided into n steps, the first step 1 includes M 1 different results, the second step includes M2 different results, …, and the n step includes Mn different results. Then this event may have n = m 1× m2× m3×…× Mn different results.