Question

claire had 5 1/7 feet of string. She ised some string to hang party decorations.Now she has 1 5/7 feet of string left.Part A choose the model that shows how much string claire used.Part B How much string did claire use?

Answer 1

PART A: the model is the first option

PART B

3 3/7

Step-by-step explanation

PART A

If she used some string, n feet of string, and she now has 1 5/7 left, the sum of those two lengths must be the original length of the string: 5 1/7

PART B

To find n we have to subtract 1 5/7 from 5 1/7:

`5(1)/(7)-1(5)/(7)`

We have to subtract the fraction parts of these mixed numbers first. Since the first fraction is greater than the second we have to "ask" the whole part for one unit. Asking for one unit means adding 7 to the numerator (because the numerator is 7 in this case) and subtracting 1 from the whole part:

`5(1)/(7)=(5-1)(7+1)/(7)=4(8)/(7)`

Now we can do the subtraction:

`5(1)/(7)-1(5)/(7)=4(8)/(7)-1(5)/(7)=(4-1)((8)/(7)-(5)/(7))=3(3)/(7)`