Imagine this: I ate 1/3 of the pizza and my friend ate 1/4 of the pizza. How much of the pizza did we eat between us? Look at the two fractions: is there any easy way to add a third and a quarter together? Have a good look at the bottom numbers before anyone answers.

The strips show three fraction sums, two added and one taken away. Look at the top two strips in each: the pieces are different sizes, then re-written so they match. The bottom strip shows what they make.

Today we work through these together on the twelfths strips, re-expressing each pair over a common denominator before we combine: first 1/3 + 1/4 over twelfths, then 3/4 - 1/3 over twelfths, then the trickier 5/6 + 1/4 over twelfths, and last 1/6 + 5/12, where sixths already fit into twelfths so only one fraction changes. Say each re-expressed fraction aloud before we shade it.