Grade
3

Which One Doesn't Belong? Dot by Dot

Look at this set of models. 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: Seven groups of 7 blue dots each. In each group, the dots make a circle. B: An array has 3 rows of 7 blue dots in 1 group, another 3 rows of 7 blue dots in another groups, and a third group has 2 rows of 7 green dots. C: An array has four rows of 7 yellow dots and 4 rows of 7 green dots. D: One group of 8 green dots and 6 groups of 8 blue dots.

Challenge

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

Share

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

Printable Version

Google doc for printing and copying

Reference for Educators

Sample problems and solutions