Grade 4 - Progress in Mathematics

Estimate with Mixed Numbers

There are 5


1

8 
lb of apples, 2 

3

4 
lb of

bananas, and 8
^15 
lb of melons at a

picnic. About how many pounds

of fruit are at the picnic?

To find about how many pounds,

estimate the sum: 5
^18 
 2 
^34 
 8 
^15 

To estimate sums of mixed numbers, use front-end estimation.

• Add the whole number parts. 5  2  8 15


• Adjust the estimate with the
  fraction parts.

Adjusted estimate: 15  1  16

There are about 16 lb of fruit at the picnic.

About how many more pounds of melons than bananas are there?

To find about how many more,

estimate the difference: 8



1

5 
^2 

3

4 


To estimate differences of mixed numbers,

use front-end estimation.

• Subtract the whole number parts.

There are about 6 more pounds of melons than bananas.

Estimate. Use front-end estimation.

1. 6
   
   1
   5
   ^9
   1

8

0 
 2.^8 

1

4 
^8 
 1

9

2 
 3.^3 

1

2 
^7 

1

6 
 4.^1 

4

9 
^4 

5

6 

5. 5
   ^23
    2
   ^49
   6. 9
   ^34
    4
   ^38
   7. 7
   120
    5
   ^12
   8. 6
   ^38
    4
   ^14
   

Fractions of 


1

2 
or

greater are about 1.

8  2 6

estimated

difference

5 
^18 
 2 
^34 
 8 
^15 

9-4

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