6⅕-2⅔. Let’s solve in steps. First take 2 away from 6 leaving 4, which we will remember for later.
Now ⅕-⅔. We need to convert these to multiples of the same unit fraction. What is the smallest number that 3 and 5 both go into? 15. 5 goes into 15 3 times and 3 goes into 15 5 times so ⅕=3 fifteenths and ⅔=10 fifteenths, because ⅓ is 5 fifteenths so two thirds is twice as much.
So we have the two fractions with a common denominator and we are going to subtract 10 fifteenths from 3 fifteenths. Oops! We can’t take 10 away from 3 because 10 is too big. Now, remember the result 4 we got earlier? We can borrow something from this. If we borrow 1 we will have another 15 fifteenths to play with and help us do the subtraction. We borrowed 1 from 4, so we only have 3 wholes left. But, we had 3 fifteenths, now we have 15+3=18 fifteenths and we can easily subtract 10 from 18 to give us 8 fifteenths.
We’re nearly done. We attach the 8 fifteenths to the whole number 3 to get 3⁸⁄₁₅.