Which One Doesn't Belong? Decimal Decisions

Look at this set of four images. 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 number line jump of plus 0.2 from 0.7. B. shows a hundredths grid with 31 boxes shaded red and 31 blue, with the expression 0.31 + 0.31. C. shows a number line that starts at 0.5, with jumps to add 0.1 and 0.02. D. shows a number line with a jump to subtract 0.38 from 1.


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?