Marisa finished painting 3/5 of a wood fence before her morning break and 3/10 of the fence between her morning break and her lunch break. explain how marisa can find the total amount of fence she painted.

I would want to multiply 3/5 by 2 to get both equations compatible. Then add them together. 3/5 times 2 is 6/10. Then add 6 + 3 = 9. The fence is 9/10 painted.

See the following:
3/5 + 3/10
Put 3/5 + 3/10 over the common denominator 10. 3/5 + 3/10 = (2×3)/10 + 3/10:
(2×3)/10 + 3/10
2×3 = 6:
6/10 + 3/10
6/10 + 3/10 = (6 + 3)/10:
(6 + 3)/10
6 + 3 = 9:

9/10