You need to do the subtraction 6 1/3 minus 3 2/3.
Since we can't subtract 2/3 from 1/3, we borrow 1 from the 6 leaving 5. The 1 we borrow from the 6 is the same as 3/3. We add that tot eh 1/3 of the 6 1/3, so now we have 5 4/3, which is the same as 6 1/3. Now we can subtract.
6 1/3 ------> 5 4/3
- 3 2/3 ------> - 3 2/3
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2 2/3
Answer: 2 2/3 yards