Subtraction with Regrouping

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Subtraction with Regrouping

• Quadruple Digits
• By Jennifer Mays
• Edited by Dr. Beth McCulloch Vinson

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• Subtraction with regrouping is used when we are
  trying to subtract from the ones place and we
  need to borrow some from the tens place.
• For example, we can take 5 from 9, but we cannot
  take 9 from 5.

9 -5 4 5 -9 x
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• 8754
• - 6876
• 8754 take away 6876.
• Can we take 6 ones away from the 4 ones?
• No. We have to go to the tens place and regroup.

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• We need to regroup the 5 tens and the 4 ones as 4
  tens and 14 ones.
• Now we can take 6 ones away from 14 ones leaving
  8.

8
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• We need to regroup 7 hundreds and 4 tens as 6
  hundreds and 14 tens.
• Now we can take 7 tens away from 14 tens leaving
  7.

78


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• We need to regroup the 8 thousands and 6 hundreds
  as 7 thousands and 16 hundreds, then subtract 8
  from 16 leaving 8.
• We also subtract the 6 from the 7 leaving 1.

1878
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• 8,754 minus 6,876 equals 1,878.

1878
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• Lets recap. Subtract without regrouping. 5
  minus 3 equals 2.

5 -3 2
_______________
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• If you have a number that is too small, then
  regroup it from the next place of value.
• With four-digit subtraction, you may have to
  regroup up to the thousands place of value.

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• Regrouping is a tool used in subtraction and when
  learned will make mathematics fun to do.

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The End