Which One Doesn't Belong? Missing Numbers

Look at this set of four equations. 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!

In A, 324 minus 'd' = 162. In B, 568 + 576 = 's'. In C, 870 = 70 + 'a'. In D, 'm' + 432 = 440.


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


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