Find the following values without a calculator.
For 7 and 10,
- what is the first common multiple?
- what is the second common multiple?
- what is the fourth common multiple?
(a)
Multiples of 7: 7, 14, 21, 28, 35, 42, 49
Multiples of 10: 10, 20, 30, 40, 50
First common multiple = 70
(a)
70 x 2 = 140
Second common multiple = 140
(a)
70 x 4 = 280
Fourth common multiple = 280
Answer(s): (a) 70; (b) 140; (c) 280