Gordon put 2 buckets of water and then 4/5 of a bucket of water.
If you add them you get that
The 2 buckets represent "wholes", you can express them as fractions, using the same denominator as the given fraction.
1 whole can be expressed as 5/5
2 wholes is then 10/5
Now add both measures:
You can express the answer
Buckets of water