Transcript File

Warm Up
Round the following decimals to the nearest whole
number then solve.
1)
2)
3)
4)
23.05 + 10.9
5.006 – 2.4
16.2 + 3.5 + 14.98
25.1 – 17.02 – 3.25
Review
1. Underline the whole number.
2. Look at the number in the place value to
the right (tenths place)
3. Five or more, round up to the next
number. Four or below, the number stays
the same.
Example: 9.4 + 2.7 + 12.7
Objective
Students will…
• Solve problems by adding or subtracting
decimals.
*** Adding & Subtracting Decimal Notes # ***
Adding and Subtracting Decimals
1) Line numbers up vertically.
2) Make sure the decimals and place values
are lined up.
3) Fill in any blanks with zeros.
4) Bring the decimal straight down to the
answer.
5) Add or subtract as if they are whole
numbers.
Adding Decimals
Example: 76.69 + 51.37
1) Line up the decimal points:
76.69
+51.37
2) Bring down the decimal, then add.
76.69
+51.37
Adding Decimals
Example: 12.924 + 3.6
1) Line up the decimal points and fill in 0’s:
12.924
+ 3.600
2) Then add.
12.924
+ 3.600
Subtracting Decimals
Example: 18.2 - 6.008
1) Line up the decimal points.
18.2
- 6.008
2) Add extra 0‘s, then subtract.
18.200
- 6.008
Practice
1)
2)
3)
4)
5.798 + 34.09 + 0.6
23.067 + 121.036
34.987 – 23.078
2.167 – 2.15
Answers
1)
2)
3)
4)
40.488
144.103
11.909
0.017
Menu Activity #
- Pick a partner
- I will pass out menu’s. You will “order”
food trying to stay within budget.
- I will be passing out coupons to help you
save money!
Dollar Words #
- Each letter cost a certain amount of
money
- Try to create words that cost $0.50, $1.00,
$1.50, $2.00, $2.50, $3.00
- What is the value of your name?
- Challenge- What do you think the most
expensive word is?
Challenge Activity #
Please get your warm up worksheet from the back of the
room.
-- You will only use numbers 0-9 once to fill in the blanks
0, 1, 2, 3, 4, 5, 6, 7, 8, 9
Review
Solve the following problems:
1.
2.
3.
4.
6.135 – 4.289
67.89 + 568.9
125.14 – 96.087
(65.4 – 45) + (247 – 0.8)
Answers
1.
2.
3.
4.
1.846
636.79
29.053
266.6
Multiplying Decimals #
• Multiplying decimals is just like multiplying
whole numbers.
• After multiplying, you must determine how
many digits to leave to the right of the
decimal point.
• Add the number of digits to the right of the
decimal point in both factors together to
determine how many digits are in your
answer.
Multiplying Decimals
Example: 6.74 × 9.063
Multiplying Decimals
Example: 4.032 × 4
1) Multiply 4032 by 4 to get 16128.
2) There are three decimal places in 4.032
and zero decimal places in 4, so place the
decimal three digits from the right in your
answer:
4.032 × 4 = 16.128
• 9063 x 674 = 6108462
• 6.74 x 9.063 = 5 decimal places
• 61.08462
Hint!
• If it is 0 tenths, drop the zero
• For example: 3.0 x 0.07 becomes 3 x 0.07
Practice:
1) 0.9 x 0.03
4) 1.6 x 0.08
2) 4.5 x 0.5
5) 0.66 x 2.0
3) 0.31 x 0.7
6) 3.04 x 0.6
Word Problems
1. Jill measures some scrap boards in her garage to
see if she has enough to make a border around her
garden. She needs 10 meters total. The boards
measure 2.75 meters, 3.2 meters, 1.65 meters, and
2.6 meters. Does Jill have enough?
2) If we give the store clerk a $20 bill for a
shirt that costs $16.95, how much change
should we expect to get back?
3) Bob wants to buy a sweater that cost
$35.75, a shirt for $19.95, and slacks for
$27.50. How much change would he get
if he gives the clerk $100?
Answers
1. 2.75 + 3.2 + 1.65 + 2.6 = 10.20 meters
She does NOT have enough.
2. 20.00 – 16.95 = 3.05
He should get $3.05 in change.
3. 35.75 + 19.95 + 27.50 = 83.20
100.00 – 83.20 = 16.80
He should bet $16.80 in change
Warm Up
Copy down problems then solve
1)
2)
3)
4)
5)
6)
7)
8)
6.02 + 3.015
0.014 + 2.3 + 17
7. 6 - 4.26
13.8 - 12.43
25.4 - 0.045
10. 75 x 0.13
0.25 x 6.4
13.2 x 1.25
Answers
1)
2)
3)
4)
5)
6)
7)
8)
9.035
19.314
3.34
1.37
25.355
1.3975
1.6
16.5
Steamboat Pizza Port
- Please get out a separate sheet of paper.
- Read the following passage. You need to use
your decimals to figure out how much Holly’s
Birthday Party cost her parents.
- Who will be the first person to find the correct
answer?
- DO NOT WRITE ON THE WORKSHEET