Directions
Let's practice reducing the ratio 4:12 to lowest terms.
Find the largest number that divides evenly into both 4 and 12. In this case the largest number that divides evenly into 4 and 12 is 4. So we call 4 the greatest common denominator of 4 and 12.
4/4 = 1
12/4 = 3
So, the reduced ratio is 1:3.
Check that no number other than 1 divides evenly into both terms in the ratio 1:3.
If that's the case, the ratio is written in the lowest terms.