Transcript Divide. Estimate to check whether the answer is reasonable.

01/05/10
Divide Decimals
#5
LT: I will divide decimals.
Warm Up:
1) 5×6
4) 9×6
7) 6×2
10) 6×6
2) 1×6
5) 6×10
8) 6×3
11) 6×100
3) 4×6
6) 6×8
9) 7×6
12) 6×11
Today’s Plan:
-Multiplication Practice
-Correct Homework
-Divide Decimals
Learning Target:
-I will divide decimals.
01/05/10
Divide Decimals
LT: I will divide decimals.
Timed Test 1-5
Today’s Plan:
-Multiplication Practice
-Correct Homework
-Divide Decimals
Learning Target:
-I will divide decimals.
#5
01/05/10
Divide Decimals
LT: I will divide decimals.
Correct Homework
Today’s Plan:
-Multiplication Practice
-Correct Homework
-Divide Decimals
Learning Target:
-I will divide decimals.
#5
4-4 Dividing Decimals by Integers
Additional Example 1A: Dividing Decimals by
Integers
Divide. Estimate to check whether the answer
is reasonable.
A. 36.75 ÷ 7
5. 25
7 ) 36.75
–35
17
–14
35
–3 5
0
Estimate
35 ÷ 7 = 5
Course 2
Place the decimal point for the answer
directly above the decimal under the
division symbol.
Divide as with whole numbers.
5.25 is a reasonable answer.
4-4 Dividing Decimals by Integers
Additional Example 1B: Dividing Decimals by
Integers
Divide. Estimate to check whether the answer
is reasonable.
B. 0.87 ÷ 3
0.29
3 ) 0.87
–6
27
–27
0
Estimate
0.9 ÷ 3 = 0.3
Course 2
Place the decimal point for the answer
directly above the decimal under the
division symbol.
Divide as with whole numbers.
0.29 is a reasonable answer.
4-4 Dividing Decimals by Integers
Remember!
When you divide two numbers with
different signs, the answer is negative.
Course 2
4-4 Dividing Decimals by Integers
Additional Example 1C: Dividing Decimals by
Integers
Divide. Estimate to check whether the answer
is reasonable.
C. 82.08 ÷ (–27)
3 .0 4
27 ) 82.08
–81
10
–0
1 08
–108
0
82.08 ÷ (–27) =
Estimate
90 ÷ –30 = –3
Course 2
The signs are different.
Think: 82.08 ÷ 27.
Place the decimal point for the answer
directly above the decimal under the
division symbol.
–3.04
The answer is reasonable.
4-4 Insert
Lesson
Titleby
Here
Dividing
Decimals
Integers
Try This: Example 1A
Divide. Estimate to check whether the answer
is reasonable.
A. 39.16 ÷ 4
9. 79
4 ) 39.16
–36
31
–28
36
–3 6
0
Estimate
40 ÷ 4 = 10
Course 2
Place the decimal point for the answer
directly above the decimal under the
division symbol.
Divide as with whole numbers.
9.79 is a reasonable answer.
4-4 Insert
Lesson
Titleby
Here
Dividing
Decimals
Integers
Try This: Example 1B
Divide. Estimate to check whether the answer
is reasonable.
B. 0.56 ÷ 4
0.1 4
4 ) 0.56
–4
16
–16
0
Estimate
0.6 ÷ 4 = 0.15
Course 2
Place the decimal point for the answer
directly above the decimal under the
division symbol.
Divide as with whole numbers.
0.14 is a reasonable answer.
4-4 Insert
Lesson
Titleby
Here
Dividing
Decimals
Integers
Try This: Example 1C
Divide. Estimate to check whether the answer
is reasonable.
C. 65.16 ÷ (–12)
5 .43
The signs are different.
12) 65.16
–60
Think: 65.16 ÷ 12
51
–4 8
Place the decimal point for the answer
36
directly above the decimal under the
–36
division symbol.
0
65.16 ÷ (–12) = –5.43
Estimate
The answer is reasonable.
60 ÷ –12 = –5
Course 2
01/05/10
Divide Decimals
•Assignment
•Page 208 #8-14
Today’s Plan:
-Multiplication Practice
-Correct Homework
-Divide Decimals
Learning Target:
-I will divide decimals.
#5
Division Vocabulary
• The dividend is the number that is being divided.
• The divisor is the number that the dividend will be divided by.
• The quotient is the number of times the divisor will go into the
dividend. (The answer to the division problem.)
dividend ÷ divisor = quotient
or
quotient
divisor )dividend
• In this example 5 is the divisor, 36 is the dividend, 7.2 is the
quotient.
7.2
5 ) 36.0
36 ÷ 5 = 7.2
– 35
10
– 10
0