What number does 14 and 21 go into?

Answer 1

To find all common multiples of two numbers, you first need to split them into their prime factors:

21 = 3x7

14 = 2x7

The next step is to identify any common factors. In this case, both numbers have 7 as a factor so we can discard one 7. Take every other prime factor (2, 3 and 7) and multiply them together to get the LCM:

2x3x7=42

To find any other common multiple, you simply multiply this number by an integer (2,3,4...). By doing this, you find that the first few numbers that 21 and 14 both go into are:

42, 84, 126, 168...

Answer 2

42