Question

Explain how you you can tell 4/9 is in the simplest form

Answer 1

Because this i s what my teacher taught me

What it's divisible by

2x 4 is divisible but not 9
3x none are divisible by three
4x only 4
And you only go up to the numerator there for 4/9 is in simplest form

Answer 2

Because it cannot be reduced any further.