Friday, 19 February 2016

Addition and Subtraction Strategies

This week we are busy working on our addition and subtraction strategies when working with 2 and 3 digit numbers. The first strategy students have been introduced to is called number hops. 

In this strategy, students start at the first number. They then draw out their "hops" to find the solution. In the question above, students draw two big hops back to take away the two groups of ten, then draw six smaller hops to take away the ones. They record the numbers as they count back, finally arriving at the solution.
This strategy is great for students who still need to see the process to fully understand how to arrive at the correct solution.

Another strategy we have been using is called "Tens and Ones".

In this strategy, students start out with the whole first number, 75, and then take away the 20 from 26. Once they have calculated that solution, they take away the remaining ones to come up with the final answer. Over the next few weeks students will work on subtracting, using these strategies, or a personal strategy that they can use and explain correctly.

If you ever have any questions about these, or any other strategies, please let me know and I can help explain.

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