Lisa, it seems that the pizza is cut into 12 slices. Morgan ate 3, leaving 9.
Megan ate 1/6, which equals 2/12, so now there are 7 slices left.
Emma ate one slice, so we are down to 6 slices.
We know that 1/3 = 4/12, so now we have 2 slices left, and we already said that 2/12 = 1/6, so there is 1/6 of the pizza left.
Hope this helps!