Which One Doesn't Belong? Colorful Calculations

Look at this set of four pictures. Decide which one doesn’t belong with the other three. Use math words to describe your thinking. There are many ways to think about each one!

A. shows a 7 by 8 red rectangle. B. shows 2 blue rectangles joined at the bottom. The dimensions could by 6 by 3 for both. Or, one could be 3 by 3 and the other 3 by 9. C. shows a 12 by 3 rectangle. One part is 10 by 3 and shaded green. The other part is 2 by 3 and shaded pink. D. shows a 9 by 4 orange rectangle.


See if you can find reasons why each of the pictures might not belong with the other three.


Explain your thinking to someone else. Do they have different reasons why one doesn't belong?