Doubling

Doubling: What is it?

Student first learn about doubling as an addition of two groups. Once students know the double facts (two times tables), they can apply this knowledge to the four times table. Students will find a double, and then double again to find the answer times 4.

Doubling FINAL.mp4

Overview

Students start using the doubling strategy first to just double once, but they may begin to notice that when you double one factor, you are doubling the number of groups, which also doubles the product.

Doubling shows that the student is beginning to understand proportional reasoning. 'With proportional reasoning, children see that for two quantities in a proportional relationship, one is a constant multiple of the other' Lawson pg. 133.

Students may not represent their doubles using a ratio table, but this can be encouraged for organization.

Doubling is also important as students make connection to their 2x multiplication facts.

Supporting Students Using Doubling

Supporting students to use doubling may include helping them to recognize the prime factors of 4, 8, 16 and 32. Also, doubling can be difficult to track, especially when the number of groups isn't one of the doubles multiples. Encouraging students to record their doubles in a ratio table can help with organizing and keeping track.

Where to Next?

Once students are efficient with doubling, students should be encouraged to begin to try Doubling & Halving, Using a Ratio Table and Using Familiar Facts.

Building Fact Fluency

Multiplication is the inverse operation and can be used to support division. Ensuring students are confident and have solid understanding of familiar facts, particularly x2, x5, and x10 will be beneficial for divisional thinking. Building arrays with square tiles will help students connect to the visual representation of an open array.

Spinning for Doubles

In this game, students work to build fluency with their single digit doubles facts (4x2, 5x2 etc). This game can also be modified for fluency with larger numbers.

Spinning for Doubles (French)

Dans ce jeu, les élèves s'efforcent de développer leur fluidité avec leurs faits à un chiffre (4x2, 5x2, etc.). Ce jeu peut également être modifié pour la fluidité avec de plus grands nombres.

Last One to School

Players race against one another to empty their houses, getting all of the students to school. This game focuses on doubles using a spinner or standard die. To offer more challenge, this game can be modified to use larger numbers.

http://www.eworkshop.on.ca/edu/resources/guides/guide_math_k_6_volume_5.pdf

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