Grade 2 Math Adding Two Digit Numbers
Adding Two Digit Numbers
Two
Digit Numbers:
The
numbers from 10 to 99 (ten to ninety-nine) are two-digit numbers.
Adding 1 digit number and 2 digit number:
Suppose, a one-digit number is 3 and a two-digit number is 15.
Now,
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T
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O
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3
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1
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5
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1
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8
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1.
First add two ones place digit, 3 + 5 = 8.
2.
Then add two tens place digit, 0 + 1 = 1. [if any place value is unavailable,
then use o]
3.
So, the sum will be 18.
Again,
Suppose,
a one-digit number is 5 and a two-digit number is 27.
Now,
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T
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O
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5
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2
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7
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3
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2
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1.
First add two ones place digits, 5 + 7 = 12.
2.
The sum of 1st step also has a ten place digit that is 1, so add
three ten place digits, 0 + 2 + 1 = 3. [if any place value is unavailable, then
use o]
3.
1st step summation’s one place digit and 2nd step summation’s
tens place digit make 32.
4.
So, the sum is 32.
Adding two 2 digit numbers:
Suppose,
a two digits number is 23 and the other two digits number is 15.
Now,
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T
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O
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2
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3
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1
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5
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3
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8
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1.
First add two ones place digit, 3 + 5 = 8.
2.
Then add two tens place digit, 2 + 1 = 3.
3.
So, the sum will be 38.
Again,
Suppose,
a two digits number is 26 and other two digits number is 35.
Now,
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T
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O
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2
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6
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3
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5
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6
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1
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1.
First add two ones place digits, 6 + 5 = 11.
2.
The sum of 1st step also has a ten-place digit that is 1, so add
three ten-place digits, 2 + 3 + 1 = 6.
3.
1st step summation’s one place digit and 2nd step summation’s
tens place digit make 61.
4.
So, the sum is 61.
(a)
Add:
(i)
26 + 42
(ii)
53 + 36
(iii)
26 + 37
(iv)
56 + 16
Solution:
(i)
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T
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O
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2
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6
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4
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2
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6
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8
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à
Sum of ones place digits: 6 + 2 = 8.
à
Sum of tens place digits: 2 + 4 = 6.
à
So, the sum is 68.
(ii)
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T
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O
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5
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3
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3
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6
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8
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9
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à
Sum of ones place digits: 3 + 6 = 9.
à
Sum of tens place digits: 5 + 3 = 8.
à
So, the sum is 89.
(iii)
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T
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O
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2
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6
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3
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7
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6
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3
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à
Sum of ones place digits: 6 + 7 = 13.
à
Sum of tens place digits: 1 + 2 + 3 = 6. [1st tens place digit = 1st
summation’s tens place digit]
à
So, the sum is 63.
(iv)
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T
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O
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5
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6
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1
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6
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7
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2
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à
Sum of ones place digits: 6 + 6 = 12.
à
Sum of tens place digits: 1 + 5 + 1 = 7. [1st tens place digit = 1st
summation’s tens place digit]
à
So, the sum is 72.
(b)
Find the sum:
(i)
25 + 12
(ii)
32 + 3
(iii)
44 + 31
(iv)
53 + 24
(vi)
16 + 12
(vii)
36+ 45
Answer:
(i)
25 + 12 = 37
(ii)
32 + 3 = 35
(iii)
44 + 31 = 75
(iv)
53 + 24 = 77
(vi)
16 + 12 = 28
(vii)
36+ 45 = 81
(c)
Find the sum:
(i)
33 + 57
(ii)
32 + 55
(iii)
36 + 26
(iv)
58 + 34
(v)
11 + 33
(vi)
32 + 52
Answer:
(i)
90
(ii)
87
(iii)
62
(iv)
92
(v)
44
(vi)
84
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