# Our objective today is to review Adding and Subtracting Fractions. - PowerPoint PPT Presentation

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## Our objective today is to review Adding and Subtracting Fractions.

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### When I think of fractions, I always think of Pizza. Pizza will be our theme today! – PowerPoint PPT presentation

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Title: Our objective today is to review Adding and Subtracting Fractions.

1
Our objective today is to review Adding and
Subtracting Fractions.
• When I think of fractions, I always think of
Pizza. Pizza will be our theme today!

2
Some Warm Ups
• Write the following as fractions.
• (1) 2 out of 5 slices have mushroom.
• (2) Circles that are colored green.
• (3) Circles that are not colored.
• (4) There are 3 pies. 2 pies and three out
of eight slices
• of a third pie have anchovies.

3
Estimating Sums and Differences
• A benchmark is a number used to replace fractions
that are less than 1.
• We use a benchmark of 0, ½, and 1 when estimating
sums and differences of fractions.

Description Examples Benchmark
Numerator is very small when compared to denominator 1/8, 3/16, 2/25, 9/100 0
Numerator is about one half of the denominator 3/8,9/16,11/25,52/100 1/2
Numerator and denominator are close to each other 7/8,14/16,23/25,95/100 1
4
• Choose a benchmark for the measurement inch
• 7 is half of 16
• ½ inch is the benchmark
• Choose a benchmark for inch
• 1 inch is the benchmark

5
• Estimate

6
• Estimate
• Estimate each sum or difference
• (1) ½ (2)
2

7
Adding and Subtracting with Like denominators
• To add or subtract fractions with like
denominators, add (subtract) the numerators and
keep the same denominator.
• Find

8
• (1) At a pizza place, 4/12 of a pepperoni pie and
7/12 of a vegetable pie were sold. How much more
vegetable pies than vegetable pies were sold?
3/12
• Which solution to is correct?
• The first equation is correct.

9
Adding and Subtracting with Unlike denominators
• Write the fraction using a common denominator
• Perform the operation in the numerator.
• Denominators remain the same.

10
• The famous sauce recipe calls for ¼ cup of pepper
and cups of oregano. How much more oregano
than pepper is needed?
• Find 5/6
• Find 1/3

11
Mixed Numbers
• When you say I ate a slice and a half of pizza,
or I have a pizza party to attend at quarter pass
five, you are using mixed numbers.
• Mixed number is a whole number and a fraction
• Write as a mixed number
• ? 6
• Write as a mixed number. 1 ½

12
• You can find the sum of mixed numbers by adding
the whole number and fractions parts separately.
Then you combine the two parts to find the total.
• 8 ? 8 ? LCD is 4. Write fractions
with same denominator.
• 6 ? 6
• ____________
• 14 ? Add whole numbers, and then
fractions.

13
• Lets take a break!

14
1. The depth of a pizza pan is 2 ½ cm deep. After
baking the pizza rises 1 ¾ cm above the pan. How
deep is the pizza? Remember to convert improper
fractions to mixed number. 4 ¼ cm

15
Subtracting Mixed Numbers
• When you subtract mixed numbers, you need to
write the fractions with a common denominator.
Then you can subtract the whole numbers and the
fractions separately.
• Fresh vegetables are grown for toppings. Zesty
tomatoes are taken from a plant that is 11 ¾
inches tall. A mushroom plant is 7 5/8 inches
tall. What is the difference between the heights
of the plants.
• 4 1/8inches

16
Renaming a Whole Number
• Find 7 2
• How would you convert 7 to a mixed number?
Remember to use 8 as the denominator in this
case!
• 7 ? 6 ? Rename 7 as 6 1 6
• - 2 ? - 2 ? Subtract the whole
numbers. Then subtract the _____________
fractions.
• 4

17
• Giorgio made 10 pepperoni pies for lunch. He
sold 7 ¼ pies. How many pies were left over from
lunch? 2 ¾ pies
• Find 5 3 1 1/3

18
Renaming a Mixed Number
• Find 9 - 1
• Here we face a problem. Using the LCD 8, the top
numerator is smaller than the bottom numerator.
• ? 9 ? 8 Rename 9 as 8 1 or 8
• -1 ? -1 ? -1
• _________________
• 7

19
• The vegetable man delivers 7 pounds of fresh,
red, ripe tomatoes on Wednesday. 5 ¾ pounds of
tomatoes were delivered on Tuesday. How much more
tomatoes were delivered on Wednesday than
Tuesday? 1 5/12

20
• The benchmark for 4/5 is ______. 1
• Using benchmarks 0, ½ and 1 estimate the sum of
1 ½
• Find each sum or difference
• (a) 1/2 (b) 3/5
• Mario the delivery boy rode his bike miles to
deliver his first order. His second order was
miles. What was the total distance Mario rode
his bike? 13/15 miles

21
• Out of 6 pizza pies, 2 did not have any
toppings. How many pizza pies had toppings.
3 3/5pies
• 25 - 8 16 7/9

22
Dont forget the dessert
• 8. Tonys pizzeria is famous for its desserts.
The following is the ingredients for its mouth
watering recipe for its Chocolate Chip Cookie
Pizza. This recipe serves 12.
• How much chocolate chips would be needed to serve
24 people? 2 2/7
• How much more chocolate chip dough is needed than
caramel topping? 11/12
• What is the total amount of chocolate chip and
pecan needed? 2 9/14

Ingredients 2 2/3 cup refrigerated chocolate
chip cookie dough 1 1/7 cup chocolate chips 1 1/2
cup pecans -- chopped 1 ¾ cup caramel ice cream
topping This recipe for Chocolate Chip Cookie
Pizza serves/makes 12
23
Congratulations, you really do understand all