2. 13 18 15

3. 12=2X2X32X3=6

18=2X3X32X5= 10

4. 1 1 1 1

45 1625

1 1 1 1

A: I found that the greatest common factor of two adjacent numbers being prime numbers must be 1, and the decimal is a multiple.

5.33 and 20

2 and 1 1

10 and 29

3 and 4

Typing is so troublesome. . .