Jon has painted 4/5 of his house. the next day he painted 2/3 of what he had left. what fraction of the house is left to paint?

Jon has painted 4/5 of his house at the first day. Then

left.

The next day he painted 2/3 of what he had left. This is exactly 2/3 from 1/5. Mathematically you should multiply these two fractions:

he has painted the second day.

Now count how much he has painted at first and second days:

Then he has to paint