Next-Gen

Jump Back Subtraction

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by bcalifano1
Last updated 3 years ago

Discipline:
Math
Subject:
Number Operations
Grade:
2,3

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Jump Back Subtraction

Dear Parents,The class is now learning about jump back subtraction! This strategy uses number lines to discover the answers of subtraction problems.

Jump Back Subtraction withMs. Califano

Why this method? Jump back subtraction allows students to use many different math concepts.

They use their knowledge on place value (tens and ones), number lines, subtraction, and addition to reach their answer.

Please work with your children on this method. Review for 10-20 minutes. You can draw out your own number lines, use this sheet, or use https://www.studyladder.com/learn/activity?id=22262 which provides a fun interactive game to practice the strategy.

Examples&Explanation

Now let's look at 3 digit numbers! The concept is the same as with two digit numbers. Now, students must be comfortable with the hundreds place value. In this particular example, it is easiest to take 517 down to 500. Now, 500 is an easy number to work with because we can ue our hundreds to subtract, then units.

Let's look at an example. The first step is to draw a blank number line. The first number that will be entered at the end is the larger number (82). Then, you mark the number all the way to the left your smaller number (49). Now, you must count how many numbers are in between using your knowledge of place value and subtraction.

If you have any questions, please feel free to e-mail me. This strategy is one that will help your children achieve confidence and security in subtraction, and you can do it too!

You can solve the problems in whichever way you feel most comfortable. The first example shows going to 80 first to make it even. Next, we know we can go all the way to 50, then jump just one more to 49. Therefore, the answer to 82-49 is 33! Another way to solve the same problem is shown below the first example.


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