Dinosaur Dentist: Doubles -1

In math we have been reviewing how to use doubles addition and subtraction sentences to solve other math facts. The students created doubles neighborhoods to relate doubles and doubles +1. I teach the students then when they are thinking about doubles +1 the two addends are "neighbors" on the number line. The concept is the same for doubles -1. If it is +1, go up one on the number line. If it is -1, go down on number on the number line. We also discussed how doubles are always even numbers and doubles +1/-1 are always odd numbers. You can learn more about the doubles neighborhoods here.

To help the students practice this concept, we played a game in the computer lab called Dinosaur Dentist. In this game, the students pull one tooth from a dinosaur, which has the same number of teeth on top and bottom (the double). They then have to use the double to determine what the answer to the double -1 would be. You can have your child play this game at home for free along with Robin Hood Doubles where the students simply identify the sum of a given double.