Question

What is the fraction 36/80 expressed in lowest terms?

Answer 1

Reduce the expression by cancelling the common factors.
9/20

Exact Form: 
9/20 

Decimal Form: 
0.45

Answer 2

Look for common factors and divide them out of both numerator and denominator at the same time.
You know they're both divisible by 2, so you can simplify to 18/40.
As you can see, both numbers are still divisible by 2, so you can go down to 9/20.
At this point, they have no common factors, so the fraction is in lowest terms.