What is three and a half minus two and two thirds?
You have to find the common denominator for the fractions, so
multiply the "half" (2) by the "thirds" (3). These two numbers
multiplied with give 6 as a common denominator. Then multiply the 1
by the 3, which will give 3/6ths, and the 2 by the other 2, which
will give 4/6ths. Hmmm! it seems that 4/6ths is greater than
3/6ths, so you have to add a whole to the 3/6ths to make a big
enough fraction to subtract. Doing that will give you 9/6ths and
you can subtract the 4/6ths.
So the answer would be 5/6ths. Try it.