Smart Subtraction Strategies!

Our third grade students use manipulatives and engage in three different strategies to deepen their understanding of subtraction.   First, they used a number line to count on from the subtrahend up to the minuend. You ‘jump’ along the number line in steps of 1, 5 or 10 until you reach the minuend and then total up the ‘jumps’ to find the difference between the two numbers.  After a couple of days of using this method, the children took it a step further by continuing to count-on from the subtrahend up to the minuend, but this time without using a number line. This week students reviewed and practiced modeling the “Re-Grouping” strategy. (You might have called this “borrowing” or “carrying” when you were learning math.) This strategy also involves use of our base-ten manipulatives as students literally trade or “re-group” groups of tens for ones in order to subtract more easily.
 Our goals are to expose our students to a number of useful strategies so they can find one that works best for them, and for them to understand and communicate the process of subtraction. We also want our students to play with numbers, algorithms and strategies and to know that there is always more than one way to solve a math problem. Ask your student which strategy he/she likes best and to model it for you at home.
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