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Lesson 3: Estimating Decimal Sums and Differences


 1. 
Sara is collecting white, blue, yellow, and red buttons. She has a jar containing 1000 buttons. Each button represents 0.001 of the buttons in the jar.
             mc001-1.jpg
If 0.342 of the buttons are white, 0.176 are blue, and 0.238 are yellow, estimate the sum of the three decimals.
a.
0.500
b.
0.600
c.
0.800
d.
0.700
 

 2. 
Use your answer from question 1 to estimate the number of buttons that are red.
a.
0.300
b.
0.200
c.
0.400
d.
0.700
 

 3. 
In another jar with 1000 buttons, there are 0.294 yellow, 0.203 red, and 0.379 blue. Estimate the sum of the three decimals.
a.
0.800
b.
0.900
c.
0.700
d.
1.000
 

 4. 
Use your answer from question 3 to estimate the number of buttons that are white.
a.
0.200
b.
0.300
c.
0.100
d.
0.000
 

 5. 
A jar contains green, yellow, black, and red jelly beans. There are 100 jelly beans in the jar. Each jelly bean represents 1 hundredth of the total number.

If 0.37 are yellow, 0.21 are black, and 0.18 are green, estimate the sum of the three decimals.
a.
0.60
b.
0.70
c.
0.80
d.
0.90
 

 6. 
Use your answer from question 5 to estimate the number of jelly beans that are red.
a.
0.20
b.
0.10
c.
0.30
d.
0.50
 

 7. 
In another jar with 100 jelly beans, 0.29 are yellow, 0.20 are red, 0.37 are black, and 0.14 are green. Estimate how many more black jelly beans there are than green jelly beans?
a.
0.20
b.
0.30
c.
0.40
d.
0.10
 

 8. 
Estimate the total number of jelly beans from question 7 that are black and yellow.
a.
0.40
b.
0.50
c.
0.70
d.
0.60
 

 9. 
Estimate to determine the missing number.
     100.00 - 36.62 = d
a.
40
b.
70
c.
60
d.
50
 

 10. 
Estimate to determine the missing number.
     1.375 + 2.117 + 5.587 = a
a.
9.200
b.
9.100
c.
8.900
d.
8.800
 



 
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