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Fractions.notebook
1
October 19, 2011
FractionsFractions are used to name a part of a group or whole. There are two parts of a fraction, the numerator and denominator.
4 numerator (parts of the whole being described)8 denominator (parts that make up the whole)
Equivalent Fractions
Equivalent fractions are two or more fractions that are equal to the same amount.
3 64 8
are equivalent fractions because they are the same amount.
Equivalent fractions can be made by multiplying or dividing (evenly) the numerator and denominator by the same number.
Lowest Terms
Lowest terms is an equivalent fraction reduced down to the smallest numerator and denominator possible.
To reduce a fraction to lowest terms you must divide both numerator and denominator by the Greatest Common Factor (GCF).
eg. 12 Factors of 10 = 1 x 12 Factors of 18 = 1 x 1818 2 x 6 2 x 9
3 x 4 3 x 6
GCF = 6 So 12 ÷ 6 = 2 Lowest Terms 18 ÷ 6 = 3
If the GCF of the numerator and denominator is 1 then the fraction is already in lowest terms.
3 64 8and
3 x 2 6 6 ÷ 2 34 x 2 8 8 ÷ 2 4
= =or
wkshts #14,44, 11
Mixed Numbers and Improper Fractions
Proper Fraction – is a fraction in which the numerator is smaller than the denominator.
23
Improper Fraction – is a fraction in which the numerator is bigger than the denominator.
53
3 23 3
Mixed Number – is a whole number and fraction combined.
+
Improper Fractions and mixed numbers combine a whole (or more than one whole) and a part of a whole.
3 3 1 73 3 3 3
or1 13 3
+ =
1
+
+ 1 2+ =
SMART Notebook
Fractions.notebook
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October 19, 2011
Converting from Improper Fractions to Mixed Numbers: ***Keep in mind that in a fraction this line means ÷ ***
So is like saying 11 ÷ 4
1. Think how many times does 4 go into 11?
2. 2 times, 4 x 2 = 8, so 2 is our whole number.
3. How many are left over? 3, so 3 is our numerator.
4. The denominator never changes.
17 5
= ? ??
11 4
11 4
11 ? 4 ?
= ?= 2 ??= 2 3?= 2 34
17 ÷ 5 = 3 Remainder 2 whole number new numerator
denominator stays the same3 25
1. Multiply the whole number by the denominator.4 x 3 = 12
2. Add the numerator.12 + 2 = 14 this is the new numerator
3. Keep the same denominator.
practice wksht. #23, 24
Converting from Mixed Number to Improper Fraction:
234
234
14 3
so =
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Fractions.notebook
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October 19, 2011
Comparing and Ordering FractionsHow can you tell if one fraction is greater than another?
I. Denominators are the same:
look at the numerators to see which one is larger or smaller24
34<
II. Denominators are different:
change each fraction to an EQUIVALENT FRACTION so each share a common denominator (LCM!!)
1. What is the lowest number both denominators can be multiply into?
2. LCM of 5 and 6 = 30
3. Using the LCM as the denominator change each fraction to its equivalent form.
4. Compare!
45
56
oreg.
5: 5, 10, 15, 20, 25, 306: 6, 12, 18, 24, 30
4 x 6 245 x 6 30
5 x 5 256 x 5 30
= =
2430
2530
< 45
56<
so
p. 47 #16, 9
BLM 2.1
III. Comparing Mixed Numbers
1. Find a common denominator and convert to equivalent fractions.
2. Compare.
1 46 1158
34
6: 6, 12, 18, 24, 308: 8, 16, 244: 4, 8, 12, 16, 20, 24
First order by whole numbers. Any numbers that the same whole number must then be ordered by the fractions.
1 4 x 4 166 x 4 24 11
5 x 3 158 x 3 24
3 x 6 184 x 6 24
1 11= ==
1 1824 111624
1524>
>
so 1 46 1158
34 > >
SMART Notebook
Fractions.notebook
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October 19, 2011
Adding and Subtracting Fractions with the Same DenominatorAdding with the Same Denominator
1. Add the numerators, denominator stays the same.
2. Reduce the fraction to lowest terms by dividing both numerator and denominator by the GCF.
Subtracting with Same Denominator
1. Subtract the second numerator from the first. Put the difference over the same denominator.
2. Reduce to lowest terms (÷ by GCF)
1 36 6
1 3 46 6 6+ =
4 ÷ 2 26 ÷ 2 3=
+ =
5 38 8
5 3 28 8 8
=
2 ÷ 2 18 ÷ 2 4
=
=
Wkshts Adding Fractions w/ Same Denominator, Subtracting Fractions w/ Same Denominator
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Fractions.notebook
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October 19, 2011
Adding Fractions with a Different DenominatorWhen adding fractions with different denominators you must first change the fractions to equivalent fractions so that they have the same denominators.
1. Find the smallest number (LCM) that both denominators can go into. LCM of 5 and 6 is 30.2. Convert to equivalent fractions with that denominator (30). Don’t forget what is done to the bottom must be done to the top.
3.Add the numerators, denominator stays the same
4.Change to a mixed number if necessary (improper) and reduce the fraction to lowest terms (÷ by GCF)
p. 55 # 4, 5, 8, 9
eg. 3 4 6 5
+ =
3 x 5 4 x 6 6 x 5 5 x 6
+ =
15 24 3930 30 30
+ =
39 ÷ 30 = 1 R9
9 ÷ 3 3 30 ÷ 3 10
1 = 1
wkshts – + fractions #12
word problems
Subtracting Fractions with a Different Denominator
When subtracting fractions with different denominators you must first change the fractions to equivalent fractions so that they have the same denominators.
1. Find the smallest number (LCM) that both denominators can go into. LCM of 5 and 15 is 15.2. Convert to equivalent fractions with that denominator (15). Don’t forget what is done to the bottom must be done to the top.
3. Subtract the second numerator from the first, denominator stays the same
4. Change to a mixed number if necessary (improper) and reduce the fraction to lowest terms (÷ by GFC)
p. 59 #6, 8, 10
eg. 4 2 5 15 =
4 x 3 2 5 x 3 15
=
12 2 1015 15 15
=
10 ÷ 5 215 ÷ 5 3=
wkshts. Subtraction Fraction #1/2
wksht. subtraction word problems
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Fractions.notebook
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October 19, 2011
Using Fraction Strips to Add and Subtract FractionsFraction Strips are used to represent each of the fractions in a fraction sentence.
I. AddingEg. + =
1. To use fraction strips to solve, first find the strip and the strip.
2. Put the strips together and find a strip that equals/matches the total length of the strips.
3. The 6ths strip matches. & are the same length together as .
4. Since is the same as and is the same as ,
+ = + =
13
12
12
13
12
13
36
26
56
12
13
56
12
36
13
26
II. SubtractingEg. =
1. To use fraction strips to solve, first find the strip and the strip.
2. Put the strips together and find a strip that equals/matches the total length of the strips. Since the matches up with ( = ) we will use the 12th strip.
3. Because we are doing subtraction, any shaded parts that match are cancelled out, the remaining shaded part is your answer.
is left so = 1012
1012
68
1012
68
68
9 12
9 12
9 12
68
1 12
1 12
wkshts BLM 2.3, 2.4
SMART Notebook
Fractions.notebook
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October 19, 2011
Using Grids to Add FractionsGrids can help you add together and subtract fractions.I. Adding
Eg. + =
2. Represent each fraction in the charts by placing counters into the charts.
is represented by counters in 3 of the 5 rows (grid 1) is represented by counters in 2 of the 3 columns (grid 2)
1. Construct two grids using the two denominators. Our denominators are 5 and 3 therefore we need a 5 by 3 grid.
3. Move counters from one grid to the other until one grid is full or all the counters have been moved (whichever comes first).
4. The filled grid (if one gets filled) equals one whole, the partially filled grid is your fraction. 4 counters in 15 squares is
So + = 4 1523
35 1
35
23
23
35
4 15
Fractions.notebook
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October 19, 2011
Eg. =
1. Construct a grid using the two denominators. Our denominators are 4 and 3 therefore we need a 4 by 3 grid.
2. Fill the grid with counters to represent the first fraction ( ).
3. We need to remove one column ( ), so we need to move counter(s) to fill a column.
4. Remove the counters from one column to represent subtracting.
5. The remaining counters represent the answer. 5 counters in 12 squares is
So =
Using Grids to Subtract Fractions
34
13
34
13
34
13
13
5 12
5 12
wkshts BLM 2.5, 2.6
SMART Notebook
Fractions.notebook
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October 19, 2011
Adding and Subtracting Mixed NumbersMethod 1 – Using Mixed Numbers
1. Find a common denominator (LCM) and convert to equivalent fractions. LCM for 3 and 4 is 12.
2. Add/Subtract the whole numbers (5 2 = 3)3. Add/subtract the numerators, denominators stay the same.
4.Improper fractions must be made into a mixed number and added to the original whole number. 9 ÷ 6 = 1 R 3. The 1 is added to whole number (2+1=3).
5. Reduce the fraction to lowest terms using the GCF.
235 142 =
3: 3, 6, 9, 12, 154: 4, 8, 12
5 2 x 43 x 4 2 1 x 34 x 3= 8 12
3 1225 =
Method 2 – Using Improper Fractions
1. Make the mixed numbers into improper fractions by multiplying the whole number by the denominator and adding the result to the numerator.
2x3+2 = 8 and 3x4+1 = 14 This is your new numerator (denominator stays the same).
2. Find a common denominator (LCM) and convert to equivalent fractions.
3. Add/subtract the numerators, denominators stay the same.
4. Convert to a mixed number. 71 ÷ 12 = 5 R 11. Answer is your whole number, remainder is your new numerator, denominator stays the same.
5.Reduce to lowest terms using GCF (if necessary
wksht. mixed fraction practice #1/2
p. 84/85 #1, 3, 4, 6, 7, 9, 10, 11
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Fractions.notebook
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October 19, 2011
Review of Fractionsp. 9394 # 16, 11, 12
Unit Exam Next Class!
Attachments
Fractions Table of Contents.docx
p. 14, 44, 11.pdf
p. 23, 24.pdf
BLM 2.1.pdf
Add Sub Frac. Same Denom.pdf
p. 31, 32.pdf
p. 33.pdf
p. 16, 17.pdf
p. 18.pdf
BLM 2.5, 2.6.pdf
p. 19, 34.pdf
BLM 2.3, 2.4.pdf
Math 7 - Table of Contents
Fractions
Page
Date
Notes – Review of Fractions
Worksheets - # 14, 44, 11
Notes – Mixed Numbers and Improper Fractions
Worksheets – # 23, 24
Notes – Comparing and Ordering Fractions
Text Assignment – p. 47
Worksheet -
Notes – Adding & Subtracting Fractions with the Same Denominator
Worksheet -
Notes – Adding Fractions with a Different Denominator
Worksheets – Adding Fractions 1-2, Word Problems
Text Assignment – p. 55
Notes – Subtracting Fractions with a Different Denominator
Worksheets – Subtracting Fractions 1-2, Word Problems
Text Assignment – p. 59
Notes – Using Fraction Strips to Add and Subtract Fractions
Worksheet -
Notes - Using Grids to Add Fractions
Worksheet -
Notes – Using Grids to Subtract Fractions
Worksheet -
Notes – Adding and Subtracting Mixed Numbers
Worksheets – Mixed Fraction Practice # 1 - 2
Text Assignment – p. 84-85
Text Assignment – p. 93-94 Unit Review
Unit Exam
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