While I was updating my Subtraction Fact Mental Strategy Count Up To Free Sample, which provides practice in identifying and discriminating between basic subtraction equations, I began thinking about concrete ways to introduce this subtraction fact strategy. I also started to realize that children who view subtraction as only meaning to take away would have a difficult time conceptualizing this strategy. (Never fear, after I get off my soapbox, there will be a link to another subtraction freebie below!)
One way to introduce this is to display equations and ask your students what they notice that is the same about all the equations. Can they solve the equations? How did they find the difference? Model how to find the difference on a number line.
When they understand this concept, they’re ready to move on to the Count Up To subtraction fact strategy. I typically prefer vertical number lines but for this activity a horizontal one made more sense. I wanted to stick with the idea of numbers or houses in a neighborhood since it is part of my anchor wall chart for this strategy. This provides a consistent visual cue. I also limited the number line to those numbers that would be used for this strategy to increase associations between the strategy and the numbers. I created number line houses 2 through 12 for group instruction and a number line strip with houses 4 through 12 for individual student use. The facts 3-2 and 4-3 can be solved by either counting down or counting up to. A number line from 4 through 12 covers the remaining basic subtraction facts for which this strategy is applicable.
Simply print the houses in color or black/ gray/ white on paper or card stock. Laminate, if desired, and cut. Place the houses in order on the carpet, a table, or a chalk/ white board. Present a Count Up To basic subtraction fact with a difference of 1, 2, or 3, such as 9 – 6. Model using counters (or button magnets on a board) how to keep 6, the lower number in your head and count up to 9, the higher number. Students can now easily visualize the difference between the two numbers! As with the Count Up strategy for addition, you will have to find ways to keep your students from counting the number they start with. While you are modeling and practicing the process, be sure to emphasize you are finding the difference between the two numbers.
When they are ready, students can use their own number line strips to practice. I would only give them three counters as this strategy is best used with a difference of 1, 2, or 3. I have also included a three counter strip that can be used as a bridge to mental fluency, instead of using fingers. Just say the lower number, then place counters as you count up to the higher number.
Students who understand and apply the Count Up To strategy for basic facts will also be able to apply it to multi-digit subtraction.
Enjoy these Numbers in the Neighborhood number lines for introducing and practicing the Count Up To subtraction fact strategy! The flashcards, an anchor wall chart, and two worksheets found in my Subtraction Fact Strategy Count Up To Free Sample may be downloaded from my TpT store.
I am delighted to have finally finished giving my subtraction fact strategy anchor charts, flashcards, and worksheets a cosmetic makeover. I also added black/ gray/ white anchor charts and quarter page size mini-charts. The strategies covered are Subtract Zero, Subtract All, Count Down, Count Up To, Doubles, Make 10, Bridge With 10, Subtract 10, Subtract 9, and Subtract 8. These resources are available individually or as a bundle.
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