Question

Draw fraction rectangles on dot paper to solve the problems.

1) Subtract: 3/5 - 1/4

2) Add: 5/6 + 1/4

3) Manny and Frank ordered pizza. Manny ate 1/4 of the pizza and Frank ate 5/8 of the pizza. How much of the whole pizza was eaten?

Answer 1

1)
`(7)/(20)`

2)
`1(1)/(12)`

3)
`(7)/(8)`

Explanation:

1) Given problem,

`(3)/(5)-(1)/(4)`

LCM(5,4) = 20,

`(3)/(5)=(3* 4)/(5* 4)=(12)/(20)`

`(1)/(4)=(1* 5)/(4* 5)=(5)/(20)`

`\implies (3)/(5)-(1)/(4)=(12)/(20)-(5)/(20)=(7)/(20)`

2) Given problem,

`(5)/(6)+(1)/(4)`

LCM(6, 4) = 12,

`(5)/(6)=(5* 2)/(6* 2)=(10)/(12)`

`(1)/(4)=(1* 3)/(4* 3)=(3)/(12)`

`\implies (5)/(6)+(1)/(4)=(10)/(12)+(3)/(12)=(13)/(12)=1(1)/(12)`

3) ∵ Pizza ate by Manny =
`(1)/(4)`

Pizza ate by Frank =
`\farc{5}{8}`

∴ Total pizza eaten =
`(1)/(4)+(5)/(8)`

LCM(4, 8) = 8,

`(1)/(4)=(2)/(8)`

Thus, total pizza eaten =
`(2)/(8)+(5)/(8)=(7)/(8)`