Find the following values without a calculator.
For 2 and 9,
- what is the first common multiple?
- what is the second common multiple?
- what is the fourth common multiple?
(a)
Multiples of 2: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50
Multiples of 9: 9, 18, 27, 36, 45
First common multiple = 18
(a)
18 x 2 = 36
Second common multiple = 36
(a)
18 x 4 = 72
Fourth common multiple = 72
Answer(s): (a) 18; (b) 36; (c) 72