1、 104

36

48

Seventy-eight

4、42

Seventy-eight

165

5988

2037

p2 1

5. Number

6. There are two others.

7、5

1

four

eight

8. Use 3* even numbers for12, 24, 36.

5、 15、25

p22

9、( 1)×(2)√(3)√

10, odd number: 435, even number: 340, multiple of 2: 350, multiple of 5: 345, multiple of 3: 435, all multiples of 2, multiple of 3: 354.

p23

There is only one factor: 1.

There is only one factor and himself: 2, 3, 5, 7, 1 1, 13, 17, 19.

There are more than two factors: 4,6,8,9, 10, 12, 14, 15, 16,18,20.

Do it: prime numbers: 17, 29, 37.

Plural numbers: 22, 35, 87, 93, 96

p24

There are 25 prime numbers: 2,3,5,7, 1 1, 13, 17,19,23,29,31,37,4.

Everything except 1 is a composite number.