Answer: He has planted 2/3 and there is 1/3 left to plant.
Explanation: You need to add your fractions together, because each of those is a section of the garden and you need the total of how much of the garden he has planted.
This isn’t too difficult because the denominators are the same.
5/12 + 3/12 = 8/12
It is 8/12 because since the denominators are the same, you just need to add the numerators. Imagine you have a pie that’s cut into 12 pieces, and you and your friends take 5, and then your family takes 3. How many or gone now? 8 pieces. From how many pieces? 12 pieces. So 8/12 pieces are gone.
So Peter has planted 8/12 of his garden. This however, can be simplified, because both of those numbers divide by 4.
8/4 = 2
12/4 = 3
So 8 is now 2, and 12 is now 3.
This is now 2/3.
If there is 2/3 gone, you need to figure out how much is left to get you to 1.
In this instance, 1 can be rewritten as 3/3, because 3 divided by 3 is 1.
In order to get from 2/3 to 1, you need to add 1/3, one more third to the two thirds you already have.
This means Peter has 1/3 left to plant.
Hope this helps :)