Math Strategy: Counting on from the Larger Number
Math Strand: Number Sense and Numeration – Addition and Subtraction
Overview:
In this strategy, students take Counting on to the next level. Counting on from the larger number means that you start with the biggest number in an equation, and then count on from there. For example, to add 5+3, students start with "5" in their heads, and then count up 3 more, "6, 7, 8." The counting on strategies works best when used for adding 1, 2, 3, or 4 to a larger number. If students try to count on with numbers higher than 4, it gets confusing, and mistakes happen because it is difficult to track. Counting on is an effective beginning addition strategy. Once students learn other more efficient strategies, they will begin using counting on in a more sophisticated way. For example, they will count on by jumps of ten instead of jumps of one. Or, counting on may be used with remaining addends after splitting and combining larger numbers.
How this supports student learning:
When students count on from a larger number, they know that the larger number represents a whole set. Students no longer directly model the problem, but use their fingers as a way to keep track of a count. Being able to start at the larger number demonstrates the understanding of commutative property of addition where a pair of numbers can be switched around to reduce the amount of counting required, without changing the result, for example, 5+7=7+5.
Where to next?
You can reinforce the Counting on from the Larger Number strategy by using activities that can be found in the book "What to Look For" by Alex Lawson, specifically on page 162. Once students are counting on from the larger number, support their development of the anchor of ten so they can combine their strategies of counting on and the anchor of ten.
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