Getting to a Decade Number & Taking Jumps of 10: What is it?

 This strategy can be used for addition and subtraction. Students begin to solve the question by getting to a decade number (10,20 etc.) then taking jumps to arrive at the answer.

Overview:

Getting to a decade number and making jumps forwards and backwards of 10 is a strategy that builds upon the "Counting on from the larger number" strategy. Students will add up in chunks, first moving to the nearest decade number, and making larger jumps of 10 from there. For example, when solving 28 + ? = 50, the student would add 2 to get to 30, and then make two jumps of 10 to arrive at 50.

Supporting Students Using 'Getting to a Decade Number & Taking Jumps'

As students encounter the challenge posed by adding or subtracting larger numbers, children will shift towards more efficient strategies. These strategies move along two general pathways, number-line related and splitting or decomposing strategies that lead to algorithms. Although there are two general pathways, number-line related strategies will only appear in classrooms that foster them. To support students to use this strategy, student thinking must be modeled using a number line by the educator. Intentional practice to work on modeling the strategy may include students working with decks of cards or rolling dice to create two digit numbers to add together. Using purposeful number strings will also benefit students.

Where to Next?

If students are using this strategy effectively, they could be encouraged to explore 'overshoot and return' or using 'strategic methods'.

Games & Activities to Support 'Getting to a Decade Number and Taking Jumps of 10'

Looking to learn more? Check out the recorded session!