The Fraction Pizza is an awesome way to differentiate when teaching fractions. Understand a fraction a/b with as a sum of fractions . Understand addition and subtraction of fractions as joining and separating parts referring to the same whole.
Here's a terrific post with directions and resources on how to introduce fractions using paper folding! This is great for comparing and equivalence. It also helps cut down on all the cutting and gluing in the classroom!