decimal detective multiplying decimals intermediate math ccss: 5.nbt.1, 5.nbt.7 add, subtract,...
TRANSCRIPT
Decimal DetectiveMultiplying Decimals
Intermediate MathCCSS: 5.NBT.1, 5.NBT.7 Add, subtract, multiply and divide decimals to hundredths using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Additional Information for teacher about activity: This activity encompasses; using mental math to multiply by 10, 100, 1000, estimating products of whole numbers and decimals, products of whole numbers and decimals, and product of two decimals. The teacher can select all or part of the cards for differentiation. Additional blank cards are included for teacher use. What’s included:□ Task Card in WORD□ Anchor Charts□ Student Activity Cards for self or partner directed work□ Answer Key for self-checking □ Materials Needed: number cube, markers, CHILD Activity Game Board and Challenge Question Answer Sheets□ Technology Connection: http://www.ixl.com/math/grade-5/estimate-products-of-decimals, http://www.ixl.com/math/grade-5/multiply-a-decimal-by-a-power-of-ten, http://www.ixl.com/math/grade-5/multiply-a-decimal-by-a-one-digit-whole-number, http://www.ixl.com/math/grade-5/multiply-a-decimal-by-a-multi-digit-whole-number
Copyright © 2013 Innovative Educational Programs. Reproduction rights granted to CHILD Teachers and permitted only for use as instructional material. www.ieponline.com
STATION TASK CARD ____________Station Activity Name: Decimal Detective Standard: Number and Operations in Base Ten Skill/Objective: (COPY IN YOUR PASSPORT) Multiplying Decimals Directions:
1. Work in a group of 2-3 partners. 2. You will need a set of cards, markers for each student, a number
cube, an answer card and a CHILD activity game board. 3. Shuffle cards and place face down. 4. Tallest partner goes first. 5. Pick a card, read it aloud and answer. Use the Anchor Charts to
help you solve the problems. 6. Partner to the left checks the answer. 7. If correct, roll the number cube and move that many spaces on
the board. If not correct, place the card at the bottom of the pile. 8. Take turns until someone reaches the end of the board.
Challenge: Write your answer on a Challenge Question Answer Sheet. Two years ago, a computer company had sales that totaled 6.5 million dollars. Last year the sales increased 2.5 times over the previous year. What were the sales totals last year? Reflection: I think the easiest strategy or model to use to multiply decimals is . . .
WHEN COMPLETED
□ check □ hand in
□ place in folder □ other _________________
Intermediate Math
Copyright ©
2013 Innovative Educational Programs. Reproduction rights granted to CH
ILD Teachers and perm
itted only for use as
instructional material. w
ww
.ieponline.com
Estimating - Decimal x Whole Number• Problem: Ben, Barry and Brian each have
27 cents. How much do they have altogether?
• The equation: 0.27 x 3 = ?• To solve: use estimation
0.27 x 3 =
0.30 x 3 = 0.90 or approximately 90 cents.
Copyright © 2013 Innovative Educational Programs.
Problem: Ben, Barry and Brian each have 27 cents. How much do they have altogether?
Copyright © 2013 Innovative Educational Programs.
Area Model - Decimal x Whole Number
0.27 x 3 = 0.27 + 0.27 + 0.27
0.27 x 3 = 0.81
Multiplying - Decimal x Whole Number
• Problem: Brendon was selling a car for $1,000. He had to charge sales tax of 0.65. How much tax did he charge?
The equation: 1,000 x 0.65 = Sales Tax
Step 1: Multiply 0.65 x 100 (or 102) = 65Step 2: Multiply 1,000 x 65 = 65,000Step 3: Divide 65,000 by 100 = 65,000 ÷ 100 (or 102) = 650 The tax charge is $650.
• When you multiply a decimal to get a whole number 0.65 x 100, the answer must be divided by 100 to find the actual answer.
Copyright © 2013 Innovative Educational Programs.
Area Model: Multiply - Decimal X Decimal
Copyright © 2013 Innovative Educational Programs.
0.8
0.6
Problem: What is the product of 0.8 x 0.6?
0.8 is represented by 8 columns of ten – colored in red.0.6 is represented by 6 rows of ten – colored in blue.
0.8 1 decimal place
X 0.6 1 decimal place 0.48 2 decimal places
0.48 is represented by purple: a combination of both red and blue.
Multiply - Decimal x Decimal• What is the product of 1.3 x 1.8 = ?
Copyright © 2013 Innovative Educational Programs.
1 x 1 =1
1 x 0.8 = 0.8
1 x 0.3=
0.3
0.8 x 0.3=0.24
1.0
1.0
0.3
0.8
Find the partial products.
1.0 x1.0 = 1.01.0 x 0.3 = 0.31.0 x 0.8 = 0.8
0.3 x 0.8 = 0.24
Then add the partial product.
1.0 x1.0 = 1.01.0 x 0.3 = 0.31.0 x 0.8 = 0.8
0.3 x 0.8 = 0.24 2.34The product of 1.3 x 1.8 = 2.34
1.02 x 100
0.8325 x 1000
3.625 x 100
28.6 x 10
82.593 x 1000
9.83 x 100 4.26 x 10
1 2 3
4 5 6
7 8 9
4.56 x 10 50.375 x 10
5 x 8.2 20.6 x 3.5 4 x 0.14
0.9 x 8 3.6 x 2.1 8.7 x 5.3
5.25 x 0.4 0.6 x 36 62.5 x 0.13
10
11
12
13
14
15
16
17
18
36.5 x 0.7 243 x 1.5 70.6 x 0.8
212 x 0.4 8.21 x 1.7 3.36 x 1.4
19
20
21
22
23
24
25
26
27
Number Answer
1 45.6
2 832.5
3 503.75
4 362.5
5 286
6 102
7 82,593
8 983
9 42.6
10 41
11 72.1
12 0.56
Number Answer
13 7.2
14 7.56
15 46.11
16 2.1
17 21.6
18 8.125
19 25.55
20 364.5
21 56.48
22 84.8
23 13.957
24 4.704
Answer Key for
Copyright © 2013 Innovative Educational Programs.
Text Text Text
Text Text Text
Text Text Text