In june, she bought 1/8 pound less than three times as much as she bought in may

3p - 1/8.

I am guessing that you would like an expression. Our expression would be: 3p - 1/8. In this expression, the 3p represents the 3 times as much as she bought in May. Since it is 1/8 less, we will subtract 1/8 from the 3p to get our expression.