page ?? #?-?? answers student learning goal chart lesson reflection

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Student Learning Goal Chart

Lesson Reflection

Pre-Algebra Learning Goal

Student will understand rational and real numbers.

Students will understand BLAH BLAH BLAH by being able to do the following:

• Learn to write rational numbers in equivalent forms (3.1)• Learn to add and subtract decimals and rational numbers

with like denominators (3.2)• Learn to add and subtract fractions with unlike

denominators (3.5)

Pre-Algebra

3-5 Adding and Subtracting with Unlike Denominators

Today’s Learning Goal Assignment

Learn to add and subtract fractions with unlike denominators.

Pre-Algebra


least common denominator (LCD)

Vocabulary

Pre-Algebra


To solve this problem, add and subtract rational numbers with unlike denominators. First find a common denominator using one of the following methods:

Method 1 Find a common denominator by multiplying one denominator by the other denominator.

Method 2 Find the least common denominator (LCD); the least common multiple of the denominators.

Pre-Algebra


Add or subtract.

1. +5 14

1 7

13 16

2.

12

2 38 1– 7

1 6

3. –2+ 3 5

2 3

4. Evaluate – n for n = . 138 9 16

Lesson Quiz: Part 1

–2 1 15

12

Pre-Algebra


Lesson Quiz: Part 2

Robert is 5 feet 6 inches tall. Judy is 5 feet 3 inches tall. How much taller is Robert than Judy?

5.3 4

12

2 in.3 4

Pre-Algebra


Are you ready for the FAST Track?

If YES, prepare for Ch. 3 Section 3 YES, BACK to Ch. 3 Section 3!

If NO, continue with the Ch. 3 Section 5 lesson!

Pre-Algebra


Pre-Algebra HW: page 7?? #?-??

(3-1, 3-2, 3-5)

Page ??#?-??

Pre-Algebra

3-5 Adding and Subtracting with Unlike Denominators3-5 Adding and Subtracting with Unlike

Denominators

Pre-Algebra

Warm Up

Problem of the Day

Lesson Presentation

Pre-Algebra


Warm UpAdd or subtract.

1 + – 1 5 11. 2

5

2. 7 123 – 2

3. 6.5 + –1.2

4. 3.4 – 0.9

5.3

2.5

3 5

11 12

1 3 1

Pre-Algebra


Pre-Algebra


Problem of the Day

A school installed a new phone system with four-digit extensions. How many extensions are possible?all numbers from 0000 to 9999, or 10,000

Pre-Algebra


Today’s Learning Goal Assignment

Learn to add and subtract fractions with unlike denominators.

Pre-Algebra


least common denominator (LCD)

Vocabulary

Pre-Algebra


A pattern for a double-circle skirt requires 9 yards of 45-inch-wide material. To add a ruffle takes another 2 yards. If the total amount of material for the skirt and ruffle are cut from a bolt of fabric 15 yards long, how much fabric is left?

1 3

2 5

1 2

Pre-Algebra


To solve this problem, add and subtract rational numbers with unlike denominators. First find a common denominator using one of the following methods:

Method 1 Find a common denominator by multiplying one denominator by the other denominator.

Method 2 Find the least common denominator (LCD); the least common multiple of the denominators.

Pre-Algebra


Find a common denominator: 8(7)=56.

2 7

+1 8

Multiply by fractions equal to 1.

Rewrite with a common denominator.Simplify

Additional Example 1A: Adding and Subtracting Fractions with Unlike Denominators

2 7

+1 8

7 7

8 8

23 56

=16 56

+7 56

A.

Add or Subtract. Method 1:

Pre-Algebra


The least common multiple of two numbers is the smallest number other than zero that is a multiple of the two numbers.

Remember!

1 61 +

5 8 List the multiples of each

denominator and find the LCD

Write as an improper fraction.

Multiples of 6: 6; 12; 24; 30

Multiples of 8: 8; 16; 24; 32

Rewrite with a common denominator.

5 8+

7 6

4 4

3 3

43 24=

15 24+

28 24

19 24= 1


Simplify.

5 8+

7 6

B.

Additional Example 1B: Adding and Subtracting Fractions with Unlike Denominators


Pre-Algebra


Find a common denominator 3(8)=24.

5 8

+1 3



23 24

Try This: Example 1A


=15 24

+8 24

A.

5 8

+1 3

8 8

3 3

Pre-Algebra


1 62 +

3 4 List the multiples of each

denominator and find the LCD

Write as an improper fraction.

Multiples of 6: 6; 12; 24; 30

Multiples of 4: 4; 8; 12; 16



Simplify.

3 4+

13 6

3 4+

13 6

2 2

33

B.

11 12

= 235 12=9

12+26 12

Try This: Example 1B


Pre-Algebra


Evaluate t – for t = .

Additional Example 2: Evaluating Expressions with Rational Numbers

4 5

–5 6

24 30

–25 30

1 30

=


4 5

5 6

Substitute for n.5 6

Rewrite with a common denominator: 6(5) = 30.

4 5

–5 6

5 5

6 6

Pre-Algebra


Evaluate – h for h = .

Try This: Example 2


5 9

–7 12

Substitute for h.–7 12

Rewrite with lowest common denominator (36).

–7 12–

5 9

7 12+5

9=

Simplify.41 36 or 1 5

36

21 36+20

36

–7 12–5

9

7 12+5

9

7 12+5

94 4

3 3

Pre-Algebra


Additional Example 3: Consumer Application

Subtract both amounts from 36 to find the amount of ribbon left.Write as improper fractions. The LCD is 8.

36 – 12 – 13 7 8

3 4

Rewrite with a common denominator. Simplify.

, or 9 3 8

75 8 There will be 9 inches left.

3 8

103 8

288 8

– – 110 8

103 8

55 4

288 8 – –

Two dancers are making necklaces from ribbon for their costumes. They need pieces measuring 13 inches and 12 inches. How much ribbon will be left over after the pieces are cut from a 36-inch length?

7 8

3 4

Pre-Algebra


Try This: Example 3

Subtract both amounts from 12 to find the amount of board left.Write as improper fractions. The LCD is 12.

12 – 6 – 4 3 4

5 12

Rewrite with a common denominator. Simplify.

, or 5 6

10 12 There will be inches left.

5 6

81 4144 12

– – 53 12

27 4 53 12

144 12 – –

Fred and Jose are building a tree house. They need to cut a 6 foot piece of wood and a 4 foot piece of wood from a 12 foot board. How much of the board will be left?

5 12

3 4

Pre-Algebra


Add or subtract.

1. +5 14

1 7

13 16

2.

12

2 38 1– 7

1 6

3. –2+ 3 5

2 3

4. Evaluate – n for n = . 138 9 16

Lesson Quiz: Part 1

–2 1 15

12

Pre-Algebra


Lesson Quiz: Part 2

Robert is 5 feet 6 inches tall. Judy is 5 feet 3 inches tall. How much taller is Robert than Judy?

5.3 4

12

2 in.3 4

page ?? #?-?? answers student learning goal chart lesson reflection

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