Transcript Divide a Decimal by a 2

Main Idea and New Vocabulary
Example 1: Divide a Decimal by a 1-Digit Number
Example 2: Divide a Decimal by a 2-Digit Number
Example 3: Real-World Example
Example 4: Real-World Example
• Divide decimals by whole numbers.
Divide a Decimal by a
1-Digit Number
Find 45.9  3.
Estimate 45 ÷ 3 = 15
1 5.3
4 tens divided by 3 is 1 ten.
–3
15 ones divided by 3 is 5 ones.
15
– 15
9 tenths divided by 3 is 3 tenths.
09
– 9
0
Answer: 45.9 ÷ 3 = 15.3; Compared to the estimate,
the quotient is reasonable.
Find 10.4 ÷ 4.
A. 2.1
B. 2.6
C. 21
D. 26
Divide a Decimal by a
2-Digit Number
Find 8.69  22.
Estimate
0. 3 9 5
0
–66
2 09
– 1 98
11 0
– 110
0
Place the decimal point.
Annex a zero and continue dividing.
Divide a Decimal by a
2-Digit Number
Answer: 8.69 ÷ 22 = 0.395; Compared to the
estimate, the quotient is reasonable.
Find 37.1 ÷ 14.
A. 0.265
B. 2.65
C. 20.65
D. 26.5
LUMBER Meg is purchasing lumber to build a
porch. The table shows the cost of the boards. If
Meg buys a 12-foot board, how much does it cost
per foot?
To find the cost per foot, divide $6.48 by 12.
0. 5 4
Place the decimal point.
–60
48
– 48
0
Answer: The cost of the board is $0.54 per foot.
LUMBER Meg is purchasing lumber to build a
porch. The table shows the cost of the boards. If
Meg buys a 10-foot board, how much does it cost
per foot?
A. $0.56
B. $0.57
C. $0.58
D. $0.59
CAMERA Elena and her sister are sharing the
cost of a digital camera. The camera costs
$88.50. If Elena saved $50 to buy the camera, how
much does she have left after paying her share of
the camera?
Estimate
$90 ÷ 2 = 45; $50 – $45 = 5
Step 1
Determine how much Elena will pay for
the camera.
Method 1
4 4.2 5
–8
08
– 8
05
– 4
10
– 10
0
Paper and Pencil
Place the decimal point.
Method 2
Bar Diagram
$88.50 ÷ 2 = $44.25
Elena’s share of the cost of the camera is $44.25.
Step 2
Method 1
$50.00
– $44.25
$5.75
Method 2
Determine how much Elena will have
left after paying her share.
Paper and Pencil
Bar Diagram
$50.00 – $44.25 = $5.75
Answer: Elena has $5.75 left.
EGGS Five dozen eggs cost $10.50. Find the
cost of one dozen. How much change will you
receive if you pay for one dozen eggs with a five
dollar bill?
A. $0.88
B. $2.10
C. $2.90
D. $5.50