6th Grade Math Textbook, Progress

Subtract Mixed Numbers

7-6

From a 7
 172 
-ft piece of rope, Ray cut

off 3
 152 
ft. How much rope was left?

To find how much rope was left, m, subtract:

7 
 1

7

2 
^3 
 1

5

2 
m.

First estimate: 7
 1

7

2 
^3 
 1

5

2 
^8 ^3 ^5

Then subtract.

To subtract mixed numbers with likedenominators:

Subtract the fractions.

Subtract the whole numbers.

Express the difference in simplest form.

Ray has 4
^16 
ft of rope left.

To subtract mixed numbers with unlikedenominators:

Find the LCD of the fractions.

Rename each fraction as an

equivalent fraction with the

LCD as the denominator.

Subtract. Express the difference

in simplest form.

When the fraction in the minuend is less thanthe

fraction in the subtrahend, rename the minuend.

Then subtract.

 6 
^14 
  5 
^54 

 4 
^34 
  4 
^34 

 1 
^24 
 1 
^12 

 7 
 1

7

2 


 3 
 1

5

2 


 4 
 1

2

2 
^4 

1

6 


m  4 


1

6 

 8 
^56 
 8 
^1102 

 4 
^34 
 4 
 192 

 4 
^34 
 4 
 112 

simplest

form

minuend

subtrahend

6 


1

4 
^5 ^1 

1

4 


6 
^14 
 5 
^44 

^14 
 5 
^54 

simplest form

Think

LCD of

6 and 4

is 12.

Think

4 


1

6


is close to the estimate of 5.

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