PSLE Answer the following.
- What is the first common multiple of 5 and 6?
- List all the common factors of 21 and 28. Give your answers in numbers in ascending order. (Eg $(n1), $(n2), 5)
(a)
Multiples of 5: 5, 10, 15, 20, 25, 30
Multiples of 6: 6, 12, 18, 24, 30
First common multiple: 30
(b)
Factors of 21: 1, 3, 7, 21
Factors of 28: 1, 2, 4, 7, 14, 28
Common factors of 21 and 28: 1, 7
Answer(s): (a) 30; (b) 1, 7