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Lesson 9 - Estimating Sums and Differences



 1. 

What ten is close to 57?
a.
60
b.
50
c.
55
 

 2. 

What ten is close to 32?
a.
50
b.
40
c.
30
 

 3. 

What ten is close to 86?
a.
90
b.
100
c.
80
 

 4. 

What ten is close to 65?
a.
60
b.
70
c.
50
 

 5. 

Use tens to find a number that is close to the sum 36 + 41.
a.
30 + 40 = 70
b.
40 + 40 = 80
c.
40 + 50 = 90
 

 6. 

Use tens to find a number that is close to the sum 53 + 24.
a.
50 + 20 = 70
b.
50 + 30 = 80
c.
60 + 30 = 90
 

 7. 

Use tens to find a number that is close to the sum 78 + 38.
a.
70 + 40 = 110
b.
80 + 30 = 110
c.
80 + 40 = 120
 

 8. 

Use tens to find a number that is close to the difference 52 - 17.
a.
50 - 10 = 40
b.
50 - 20 = 30
c.
60 - 20 = 40
 

 9. 

Use tens to find a number that is close to the difference 71 - 44.
a.
70 - 40 = 30
b.
70 - 50 = 20
c.
80 - 40 = 40
 

 10. 

Use tens to find a number that is close to the difference 97 - 56.
a.
90 - 60 = 30
b.
100 - 60 = 40
c.
100 - 50 = 50
 



 
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