Answer:
179/180
Step-by-step explanation:
To add fractions, you must make the denominator the same. So the closest factor of 18 and 20 is 180. So to change them into the same denominator, you multiply 18 by 10 to get 180 so you multiply 17 by 10. 170/180. And then to get 180 out of 20 is 20x9 so you multiply 1 by 9. 9/180.
170/180+9/180=179/180
