September , 2015

At your desk:1. Math Journal2. Planner3. Homework

By the end of class today:

-You will be able to fluently add, subtract,

multiply and divide decimals!

Life lessons: Be Present- Minded Be Committed to Excellence Be a Positive Force Take Action!

Adding and Subtracting Decimals

1. Line up the decimal points vertically.

2. Insert zeros so each number has the same amount of digits after the decimal point.

3. Add or subtract as with whole numbers.

4. Bring down the decimal point.

Complete Warm-Up in journalFind the value of each

expression.1.4.91 + 37.5

2.7.8 − 1.73

3.6 − 2.7

4.0.834 + 0.07

42.41

6.07

3.3

0.904

Precision Police• Is my work organized?• Does my work support my

answer?• Did I label my answer?• Did I circle or box my answer (if

applicable)?

Lesson:Operations With Decimals

Title the top of your journal page:

Focus on:Multiplying

Dividing

Multiplying with Decimals

1. Multiply as if the numbers are whole numbers.

2. Add the number of digits after the decimal point in each factor to find the number of decimal places in the product.

3. Insert zeros, if necessary, to hold place value. Delete zeros that are not necessary.

Example 1Find the value of 4.13(5.2).

Multiply as if the numbers arewhole numbers.

Insert the decimal point.

4.13(5.2) = 21.476

4.13 5.2

8 2 6 2 0 6 5 02 1.4 7 6

Move the decimal three places to the left.

PracticeMath book page 30.

Problems:• 1• 5• 10

18.6

7.54

$4.06

6.2(3)

1 .45(5.2)

$0 .29(14)

Dividing with Decimals

1. If the divisor is not a whole number, change the divisor into a whole number by moving the decimal point to the right.

2. If the decimal point in the divisor was moved, move the decimal point in the dividend the same number of places to the right as it was moved in the divisor.

3. Divide the dividend by the divisor.

4. Move the decimal point in the quotient directly above the decimal point in the dividend.

5. If necessary, insert zeros to hold place value.

Example 2Find the value of 15.12 ÷ 3.6.

Move decimals so the divisoris a whole number.

Divide as if both numbers arewhole numbers and then movethe decimal point directly upinto the quotient.

15.12 ÷ 3.6 = 4.2

Example 3Isaiah developed 30 pictures from his digitalcamera. He was charged $2.70. What pricedid he pay per picture?

To find the price per picture, find the value of the total cost divided by the number of pictures developed.

$2.70 30

Isaiah paid $0.09 per picture.Move the decimal up into

the quotient and insert zero to hold the place value.

Example 4Find the value of 5 ÷ 8.

5 ÷ 8 = 0.625

Insert zeros at the end of the dividend until there is a

remainder of 0.

The decimal point is placed in the quotient before the

first zero was inserted.

PracticeMath book page 30.

Problems:• 13• 18• 19

10.64 ÷ 5.6

1.6 /40

$ 1.68 ÷ 2.8

1.9

25

$0.60

Communication Prompt(Copy and reply in journals)

What part of dividing with decimals is the most challenging for you?

Exit Problems(Copy and reply in journals)

1.8.4(1.3)

2.0.25(1.9)

3.19.6 ÷ 7

4.7.2 ÷ 0.3

10.92

0.475

2.8

24

Homework:

1.6c Worksheet

****Remember:

You will be able to fluently add, subtract, multiply and divide decimals