six

12

18

24

30

36

Forty two.

48

54

60

66

Seventy two

Seventy-eight

84

90

86

/kloc-multiples of 0/0

10

20

30

40

50

60

70

80

90

100

common multiple

30

60

90

least common multiple

30

5. Error

Counterexample: 1 and the least common multiple of any integer.

correct

The concept of common multiple is a natural number

To rule out the possibility that two numbers are decimals, that is, two numbers are natural numbers by default here.