## Sunday, August 31, 2008

### What is Combinations Club?

This year, we will be focusing on becoming fluent with the addition combinations up to 10 + 10. In second grade, students learn these combinations over the course of the year. Combination sets include:

Make Ten (combinations of 10 with two numbers like 8 + 2)
Plus 1 (any number plus one like 1 + 8)
Plus 2 (any number plus two like 3 + 2)
Doubles (any number plus itself like 5 + 5)
Near Doubles (any number close to a double like 5 + 6)
Plus 10 (any number added to 10 like 3 + 10)
Plus 9 (any number added to 9 like 3 + 9)

Students will learn these combinations through frequent and repeated use. In school, we will be playing several games that help students learn particular combinations. Students will also play some of these games for homework, such as Plus 1 or 2 Bingo and Make 10.

We will also be using “Combinations Cards” to help students practice. We are not encouraging students to memorize these combinations! We are encouraging students to find efficient ways to solve the combinations. For example, look at the sample cards below:

We want to encourage students to efficiently (quickly and accurately) solve basic addition combinations. We are doing this by having students think of clues to help them solve the combinations. They may write the clues on their practice cards to help them. For example, if they are familiar with the double combination of 6+6, they may choose to look at 6+7 as one more than 6+6. If they are more familiar with the combination 7+7, they may choose to look at the combination as 7+7-1. There are many different ways to look at these combinations. Again, we are stressing that we are NOT looking for memorization, but efficiency and problem solving.

When your child is comfortable with a set of Combinations Club cards, he or she will receive a new set. (Often students will be asked to explain their thinking aloud on certain cards.) If they are still having difficulty with a set of cards, you will see them sent home again. If we feel they have mastered the concepts presented in those cards, a new set will be sent home. Please add the new set of cards to the previous set of cards, and keep practicing. Write any clues on the front of the cards that may help remember the combinations.