Grade
2

Which One Doesn't Belong? Base Ten Riddles

Look at the 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: I have 3 hundreds, 0 tens, and 7 ones. What number am I? B: I am the number 300 + 10 + 1. Number pieces show 3 hundreds, 1 ten, and 1 one. C: I have 2 hundreds, 5 tens, and 3 ones. What number am I? Number pieces show 2 hundreds, 5 tens and 3 ones. D: I have 3 hundreds, 4 tens, and 0 ones. What number am I? Number pieces show 3 hundreds and 4 tens.

Challenge

Find reasons why each of the pictures 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