Grade 1 Math Missing Number in An Addition Sentence
Missing Number in An Addition Sentence
How
you will find the missing member in an addition sentence?
If
the missing number is the sum of the addition sentence, then add two addends to
get the missing number.
Example:
3
+ 5 = ?
We
know, 3 + 5 = 8.
So,
the missing number is 8.
If the missing number is an addend of the addition sentence, then start counting after 1 step of the addend and count until the number of sum comes. Now calculate the no of counting steps. The counting steps will be the missing number.
Example:
5
+ ? = 8
Start
counting from 6: 6à7à8,
total steps = 3.
So,
5 + 3 = 8. Missing number = 3.
1. What is the missing numbers in these addition sentences?
a.
4 + ? = 8.
b.
? + 5 = 9.
c.
6 + ? = 8.
d.
? + 5 = 6.
Solution:
a.
4 + ? = 8.
|
Given
Addend
|
4
|
|
|
|
Start
counting
|
5
|
1
|
Counting
Steps
|
|
|
6
|
2
|
|
|
|
7
|
3
|
|
|
End
Counting
|
8
|
4
|
So, 4 + 4 = 8.
Missing
number = 4.
b.
? + 5 = 9.
|
Given
Addend
|
5
|
|
|
|
Start
counting
|
6
|
1
|
Counting
Steps
|
|
|
7
|
2
|
|
|
|
8
|
3
|
|
|
End
Counting
|
9
|
4
|
So, 4 + 5 = 9.
Missing
number = 4.
c.
6 + ? = 8.
|
Given
Addend
|
6
|
|
|
|
Start
counting
|
7
|
1
|
Counting
Steps
|
|
End
Counting
|
8
|
2
|
So, 6 + 2 = 8.
Missing number = 2.
d.
? + 5 = 6.
|
Given
Addend
|
5
|
|
|
|
Start
counting
and
End
Counting
|
6
|
1
|
Counting
Steps
|
So, 1 + 5 = 6.
Missing
number = 1.
2. Chose the correct answer.
(i).
5 + ? = 10.
a.
3
b.
2
c.
5
d.
6
(ii)
6 + ? = 6.
a.
1
b.
2
c.
0
d.
3
(iii)
1 + ? = 7.
a.
2
b.
4
c.
6
d.
9
Answer:
(i)
c
(ii)
c
(iii)
c
3. Fill in the blanks.
a.
2 + _____ = 7.
b.
3 + _____ = 9.
c.
______ + 4 = 11.
d.
______ + 3 = 8.
e.
3 + 7 = ______.
f.
6 + 5 = _______.
Answer:
a.
5
b.
6
c.
7
d.
5
e.
10
f.
11