Reflection: Modeling Make A Ten To Subtract - Section 4: Guided Practice


I realized that my students focused on the algorithm rather than on the process of rounding numbers to ten.  In order to change this habit, I need to provide students with more opportunities to manipulate numbers through composing and decomposing numbers, rounding, and counting.

Adding a step to include student use of number lines to round the number before subtracting and determining the difference between the rounded number and the actual number would help the students identify in advance the amount to add back to the difference.  

Another option would be to use a hundreds chart to help find the nearest rounded number.  

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Make A Ten To Subtract

Unit 2: Subtraction
Lesson 4 of 5

Objective: SWBAT round numbers and place value for subtracting mentally.

Big Idea: Students learn nines are easy to subtract. Just think ten...take away 1.

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