Precalculus fraction help???

Question

I am so confused. I'm bad at fractions already, and these are in radians.

In the book one of the examples says π/12 = π/3 - π/4

I don't understand how you figure out what makes π/12.
If anyone can give me any clue, it would help a lot. Thanks!

Answer 1

find a common denominator, so

pi/12 = 4pi/12 - 3pi/12 = pi/12

Answer 2

do it like regualr fractions
find a common denominator
π/12=(π/3)(4/4)-(π/4)(3/3)
π/12=(4π/12)-(3π/12)
π/12=π/12