Math Activity to Teach Doubling: Concentrating on Doubles

Game: Concentrating on Doubles
Strand: Number Sense and Numeration, Addition and beginning Multiplication
Math strategy: Doubling

Materials: 
Concentrating on Doubles cards ( BLM8 GEIM vol 5) 1 or 2 sets for each pair

Overview: 
Students can play in pairs or small groups. Similar to 'memory' or other concentration games, students place all of the cards face down and spread out on a desk or floor. Each player takes a turn, by turning up two cards at a time. The goal of the game is to match the doubles number expression with the correct sum card. If a match is found, the player keeps the cards. If a match is not found, then the cards are turned over in the same place, and it is the next player's turn. The player with the most matches wins.
*a variation on this would be to have students play individually with a timer to see how many matches he/she can find in a set amount of time.

How this supports Student Learning: 
This game provides opportunities for students to strengthen their doubles facts. Students are often able to learn certain number facts, such as doubles (e.g., 3+3 , 5+5) before others, and will use these known facts to derive answers for unknown facts (3+4 is related to 3+3 and 5+6 is related to 5+5). 
There are only ten double facts.  Students can practice learning facts by playing games such as concentrating on doubles, which will lead them to the learn the two times tables. The two times tables should be linked to student's prior knowledge about the addition of doubles.

Where to next?: 
This strategy is particularly helpful because students who know their two times table well can relate these facts to the three times table. If 2 x 4 is 8, then 3 x 4 is 8 plus one more group of 4.

They will see connections to everyday items when they think about doubles:

When students know the double facts (two times tables), they can apply this knowledge to the four times table by simply doubling the product.


Another way to help students learn doubles is by models. This helps students make connections between the models, the symbols, and the words. The emphasis is on understanding the concept and accessing the strategies for computations with multiplication.





Games to support where to next: 
Over-Easy Doubles GEIM Vol.5, pg. 73 (BLM10)
Snappy Doubles GEIM Vol.5, pg. 75 (BLM12)
Find a Friendly Neighbour GEIM Vol. 5, pg 75  (BLM13)
Spinning for Near-doubles GEIM Vol.5 pg 76 (BLM14)