Answer:
179/180
Step-by-step explanation:
<em><u>Step One</u></em>
Find the prime factors of 18 and 20
18:3*3*2
20: 2 * 2 * 5
<em><u>Step Two</u></em>
You need two 2s two 3s and one 5 for the common denominator
The common denominator is 2 * 2 * 3 * 3 * 5 = 180
<em><u>Step Three</u></em>
Put the two fractions over 180
179/180