Subtracting- add to subtract
Presentation
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Mathematics
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2nd Grade
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Practice Problem
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Easy
Standards-aligned
brooke chapman
Used 23+ times
FREE Resource
7 Slides • 6 Questions
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Subtracting- add to subtract
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Let's review place value and some mental math
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Multiple Choice
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Multiple Select
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Multiple Choice
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Multiple Select
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Multiple Choice
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Multiple Choice
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Add to subtract strategy
When subtracting three-digit numbers, we can use a number line to help us. We now use another method called adding to subtract. When we add to subtract, we count on from the smaller number to the larger number to find the difference between them.
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300 - 70 =
Remember, when we use the add to subtract strategy, we start by putting the smaller number, our part, on the far left of the open number line. We show that we are starting there with a green dot.
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300 - 70 =
We need to land on 300 from 70. So, we hop by hundreds from 70. Write and say 170, 270. We stop at 270 because another hop of 100 will take us to 370, and that is more than 300. Instead, we took took 2 hops of 100, or 200 in all, and land on 270. Now, we need to count by tens.
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300 - 70 =
We have reached 270, but we still need to get to 300. We can do this by hopping by tens. Hop and say the numbers as you count. 280, 290, 300. We hopped 3 tens, or 30, and landed on 300. We use a red dot on the number 300 to show where we are stopping.
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300 - 70 = 230
To find the difference between 300 – 70 = ____, we add the hops we have made. So there are 2 hops of 1 hundred, or 200 in all, and 3 hops of ten, which is 30. Together, 200 and 30 make 230.
We added to subtract to find that 300 – 70 = 230.
Subtracting- add to subtract
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