PSLE Answer the following.
- What is the first common multiple of 3 and 7?
- List all the common factors of 39 and 65. Give your answers in numbers in ascending order. (Eg $(n1), $(n2), 3)
(a)
Multiples of 3: 3, 6, 9, 12, 15, 18, 21
Multiples of 7: 7, 14, 21
First common multiple: 21
(b)
Factors of 39: 1, 3, 13, 39
Factors of 65: 1, 5, 13, 65
Common factors of 39 and 65: 1, 13
Answer(s): (a) 21; (b) 1, 13