Question

a recipe calls for a total of 3 2/3 cups of flour and sugar. it the recipe calls for 1/4 cup of sugar, how much flour is needed?

Answer 1

Answer:

This is very detailed as I wish to make some principles about fractions clear.

3

5

12

Explanation:

This question boils down to  

3

2

3

−

1

4

A fractions structure is that of:

count

size indicator of what you are counting

→

numerator

denominator

You can not directly add or subtract the counts (numerators) unless the size indicators (denominators) are the same.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Consider  

3

2

3

Write as  

3

+

2

3

Multiply by 1 and you do not change the value. However, 1 comes in many forms so you can change the way something looks without changing its true value

[

3

×

1

]

+

2

3

[

3

×

3

3

]

+

2

3

 

9

3

   

+

2

3

 

=

 

11

3

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Putting it all together

3

2

3

−

1

4

 

→

 

11

3

−

1

4

But the size indicators are not the same. I chose to make them become 12

11

3

−

1

4

 

→

 

[

11

3

×

1

]

−

[

1

4

×

1

]

               

→

 

[

11

3

×

4

4

]

−

[

1

4

×

3

3

]

               

→

     

44

12

     

−

 

3

12

Now we may subtract the counts

               

→

 

44

−

3

12

 

=

 

41

12

But this is the same as  

12

12

+

12

12

+

12

12

+

5

12

                         

=

 

1

2

+

2

1

2

+

2

1

2

+

5

12

 

=

 

3

5

12

Step-by-step explanation:

Answer 2

Answer:

C) 3 5/12

Step-by-step explanation: