lowest common multiple of 4,7,9?

Answer 1

Prime factor each
4 = 2 x 2
7 = 7
9 = 3 x 3

Take union of all factors, removing duplicates (none here)
Answer = 2 x 2 x 3 x 3 x 7 = 252

Answer 2

let's factor each of the two numbers: 12 = 2 x 2 x 3 52 = 2 x 2 x 13 to find the lowest common multiple, we can start with the one set of the factors that appear in both numbers - in this case, 2 x 2, then multiply in the factors that appear only in one number: x3 and x13 so the lowest common multiple is 2 x 2 x 3 x 13 or 156.

Answer 3

You need to multiply all 3. 252