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Click the mouse button or press the Click the mouse button or press the Space Bar to display the answers.Space Bar to display the answers.
Objective
Find the product of decimals and whole numbers
Vocabulary
Scientific notation
A way of expressing a number as the product of a number that is at least 1 but less than 10
and the power of 10
Example 1 Multiply Decimals
Example 2 Multiply Decimals
Example 3 Annex Zeros in the Product
Example 4 Annex Zeros in the Product
Example 5 Scientific Notation
1/5
Find 18.9 4
Write the problem vertically line up digits, not place value
Multiply 4 9 = 36
Put the one’s place value of 6 under the 4
Carry the ten’s place value of 3
3
Multiply 4 8 = 32
Add the carry of 3 to 32 = 35
Put the one’s place value of 5 under the 8
Carry the ten’s place value of 3
3
1/5
Find 18.9 4Multiply 4 1 = 4
3 Add the carry of 3 to 4 = 7
Put the one’s place value of 7 under the 1
Count the decimal places in 18.9
31
Count the decimal places in 4
0
Add the place values 1 + 0
1
Beginning on the right of the 6, place a decimal 1 place to the leftAnswer: 75.6
Answer: 100.8
1/5
Find 12.6 8
4
2/5
Find 0.56 7
Write the problem vertically line up digits, not place value
Multiply 7 6 = 42
Put the one’s place value of 2 under the 7
Carry the ten’s place value of 4
Multiply 7 5 = 35
Add the carry of 4 to 35 = 39
Put the one’s place value of 9 under the 5
Carry the ten’s place value of 3
3
4
2/5
Find 0.56 7Multiply 7 0 = 0
Add the carry of 3 to 0 = 3
Put the one’s place value of 3 under the 0
3
Count the decimal places in 0.56
2
Count the decimal places in 7
0
Add the place values 2 + 0Beginning on the right of the 2, place a decimal 2 places to the leftAnswer: 3.92
2
Answer: 3.32
2/5
Find 0.83 4
3/5
1Find 3 0.016
Write the problem vertically line up digits, not place value
Since 0.016 has more digits than 3, put it on top
Multiply 3 6 = 18Put the one’s place value of 8 under the 3Carry the ten’s place value of 1Multiply 3 1 = 3Add the carry of 1 to 3 = 4Put the one’s place value of 4 under the 1
3/5
1
Find 3 0.016
Multiply 3 0 = 0
Put the one’s place value of 0 under the 0 next to the 1
Multiply 3 0 = 0
Put the one’s place value of 0 under the 0
Count the decimal places in 0.016
3
Count the decimal places in 3
0
Add the place values 3 + 0
3
Beginning on the right of the 8, place a decimal 3 places to the left
Answer: 0.048
Answer: 0.092
3/5
Find 4 0.023
ALGEBRA Evaluate
4/5
Write the algebraic expression5g
Remember: 5g means 5 g
Replace g with 0.0091
Bring down the 5
5 (0.0091)
Write the problem vertically line up digits, not place value
Since 0.091 has more digits than 5, put it on top
0.0091x 5
ALGEBRA Evaluate
4/5
0.0091x 5
Multiply 5 1 = 5
Put the one’s place value of 5 under the 5
5Multiply 5 9 = 45Put the one’s place value of 5 under the 9Carry the ten’s place value of 4
4
5
ALGEBRA Evaluate
4/5
0.0091x 5
Multiply 5 0 = 0
5Multiply 5 0 = 0
Put the one’s place value of 4 under the 0 next to the 9
4
5
Add the carry of 4 to 0 = 4
Put the one’s place value of 0 under the 0
40
Multiply 5 0 = 0Put the one’s place value of 0 under the 0
0
ALGEBRA Evaluate
4/5
0.0091x 5
0 0455
4 Count the decimal places in 0.0914 Count the decimal places in 50
Add the place values 4 + 0
Beginning on the right of the 5, place a decimal 4 places to the left
.
Answer: 0.0455
4
ALGEBRA Evaluate
Answer: 0.0186
4/5
ASTRONOMY The average distance from Earth to the Sun is 1.5 108 kilometers. Write this distance in standard form.
5/5
Write the problem1.5 108 Use the calculatorPut 1.5 in calculator
1.5
Push the sign
Put 10 in calculator
10
Push the exponent key [yx]
yx
ASTRONOMY The average distance from Earth to the Sun is 1.5 108 kilometers. Write this distance in standard form.
5/5
1.5 108
1.5 10 yx
Put the exponent 8 in calculator
8 Push the = sign
=
150,000,000 Make sure to add the commas in the appropriate places
Answer: The average distance is 150,000,000 kilometers
Answer: 240,000 years
ARCHAEOLOGY An archaeologist claims that a particular artifact is 2.4 105 years old. Write this age in standard form.
*
5/5
Assignment Lesson 4:1 Multiplying Decimals 15 - 38 All
by Whole Numbers
