Videos
Our work in third grade math this year will emphasize a deepening understanding of mathematical concepts, including why it works to solve problems in different ways, over simply memorizing mathematical procedures. These videos highlight different methods and language I will use with students in the classroom as we approach our math work. New videos will be added as the year progresses.
Partial Sums Addition - This method is used to add multi-digit numbers. It requires students to have a solid understanding of the place value in numbers before adding. This video shows the use of partial sums addition with multiple problems. While third graders will not work with decimals in numbers until the end of the year, it is useful to see that this strategy works for many different problems.
Two additional simple videos about the partial sums algorithm can be found here. |
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Trade-First Subtraction - This method is used to subtract multi-digit numbers. It requires students to have a solid understanding of the place value in numbers before adding. While the trade-first method will be the most common method for students to use for subtraction as the year goes on, our work with subtraction also includes subtraction by counting up on a number line (as students become more proficient with this method, they will make larger jumps on the number line than shown in the video) and partial differences subtraction.
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