Which One Doesn't Belong? Dots in Two Colors

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

A. shows a row of 5 red circles. B. shows a row of 4 blue circles and 1 red circle below. C. shows 3 red circles and 2 blue circles scattered about. D. shows a row of 3 red circles and 1 blue circle.


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?