**Pattern
Block Example Using Mixed Numbers**

Assume we're using a set of pattern blocks that looks like this:

One important difference between tangram pieces and pattern blocks is that with the latter, students can make "trades", for example, 1 yellow = 2 red = 3 blue = 6 green.

The following
series of pattern blocks can be used to compute 1 2/3 + 2 1/2 and motivate one
of the algorithms for adding fractions (and mixed numbers), finding common denominators: