Grade 2 Math: 2-digit Addition with Regrouping
2-digit Addition with Regrouping [Carry Over]
When we add two numbers, then we add the digits in the same places. When we add the same place digits then the sum will be one digit number or two digits number. If the sum is two digits number then the process of addition with regrouping is applied. At this time the number of the sum’s tens place digit will carry over for the next place digits addition and if there we get two digits numbers then the same rule is applied.
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| Addition with Regrouping |
Example:
Suppose, we shall add 56 and 97.
Here, ones place digit summation = 6 + 7 = 13
13 is a two-digit number.
So, the ten-place digit of 13 will carry over.
Ten place digit of 13 is 1.
So, 1 will be added with the addition of tens place digits of 56 and 97.
Ten place digits summation = 5 + 9 + 1 = 15
So, the total Addition Process is as follows:
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Tens
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Ones
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5
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6
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9
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7
------ |
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13
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à
Ones place addition
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1
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3
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à
Regrouping of 13
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|
-----
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15
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3
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The Total process summary is:
- Add ones place digits
- Regroup the sum of ones place digits [if it is a 2-digit number]
- Add tens place digits [with regrouping tens]
- Regrouping ones and addition of tens digits make the sum.
1. Add 59 and 38
Solution:
- Add one’s place digits: 9 + 8 = 17
- Carry over 1 [ddition of regrouping rules]
- Add ten’s place digit and 1: 5 + 3 + 1 = 9
- Put 7 from one’s place addition after 9 from tens place addition.
- So, the sum is 97.
In Short Form:
59
Or, 59 + 38 = 97.
2. 65 + 48 = ?, Show with expanded form.
Solution:
- Addition of ones place digits: 5 + 8 = 13
- Carry out digit = 1 [Addition of regrouping rules]
- Addition of tens place digits: 6 + 4 + 1 = 11
- So, the sum = 113
In Short Form:
65
Or, 65 + 48 = 113.
Expanded Form of Addition:
Expanded form of 65 = 6 tens + 5 ones
= 10 tens + 1 tens + 3 ones
= 11 tens + 3 ones
= 110 + 3
= 113
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