1. Chapter 4: Multiplication with Decimals
MAFS.5.NBT.1.2,MAFS.5.NBT.2.7,

2. Vocabulary Words
decimal - A number with one or more digits to the right of the decimal point
expanded form - A way to write numbers by showing the value of each digit Ex: .074 = (0 x 1/10) + (7 x 1/100) + (4 x 1/1000)
hundredths-One of 100 equal parts Examples: 0.56, 56/100 , fifty-six hundredths
Multiplication- A process to find the total number of items made up of equal-sized groups, or to find the total number of items in a given number of groups. It is the inverse operation of division
Ones- the value of a digit in the ones position on a place-value chart
Pattern - An ordered set of numbers or objects; the order helps you predict what will come next Examples: 2, 4, 6, 8, 10
place value- The value of each digit in a number based on the location of the digit
product - the result when you multiply two numbers
tenths- One of ten equal parts Example: 0.7 = seven tenths or 7/10
thousandths-One of one thousand equal parts Example: = six thousandths or 6/1,000

3. 4.1 Patterns with Multiplication
Complete the pattern.
10⁰ x =
10ٰ¹ x =
10² x =
10³ x =
x 3.9=
10 x 3.9=
100 x3.9=
1,000 x 3.9 =
3. 1 x 6,391 =
0.1 x 6,391 =
0.01 x 6,391 =
Remember!!
10⁰ = 1
10ٰ¹ = 10 4.
n x $3.25 = $325.00
n= _____ 5.
0.1 x n = 89.5
n = _____

4. 4.2 Multiply Decimals and Whole Numbers w/Model
Use a decimal model to find the product.
5 x 0.06 =_____ x 0.24 = _____ x 0.8 = _____

5. 4.2 Cont’d Find the product by drawing a quick picture.
Video: H86dRA59&index=38
3. 4 x 0.6 = ____ x 0.67 = _____
5. 4 x 0.32 = ____

6. 4.3 Multiplication w/ decimals and whole numbers (Old school)
Use partial products or multiply by the whole number to find the solution.
6.32
X 3
4.5
X 8 X
X 19

7. 4.4 Multiply Using Expanded Form (new math)
Step 1: Rewrite the factors in expanded form, and label the model.
Step 2: Multiply to find the area of each section. The area of each section represents a partial product.
Draw a model to find the product.
19 x 0.75 = x 8.7 = x 56.1 = 10 9

8. 4.5 Problem Solving: Multiplying Money
How can the strategy draw a diagram help you solve a decimal multiplication problem?
Ex: Julie’s savings account has a balance of $57.85 in January. By March, her balance is 4 times as much as her January balance. Between March and November, Julie deposits a total of $ If she does not withdraw any money from her account, what should Julie’s balance be in November?
MODEL
JAN:
MAR:
NOV:

9. 4.5 Problem Solving: Multiplying Money
2. Manuel collects $45.18 for a fundraiser. Gerome collects $18.07 more than Manuel. Cindy collects 2 times as much as Gerome. How much money does Cindy collect for the fundraiser?
A group of friends go to a local fair. Jayson spends $3.75. Maya spends 3 times as much as Jayson. Tia spends $5.25 more than Maya. How much does Tia spend?

10. 4.6 Decimal Multiplication
Video:
Multiply. Use the decimal model
0.8 x 0.4 =
x 0.7 =
x 1.6 =
x 1.5 =
x 0.3 =

11. 4.7 Multiply Decimals
Estimate by rounding, then find the exact answer.
Estimate:
X 0.8
Estimate:
X 5.5

12. 4.8 Zeroes in the Product
Write the zeroes in the product. ALL of them!
0.2
X 0.3
X 0.7
3. Michael multiplies 0.2 by a number. He records the product as What number did Michael use?
4. In a science experiment, Tania uses 0.8 ounce of water to create a reaction. She wants the next reaction to be 0.1 times the size of the previous reaction. How much water should she use?