Transcript Tuesday, Oct 30

5 Minute Check
Complete in your notebook.
Find each sum
1. 4.9 + 3.0
2. 0.796 + 13
Find the difference.
3. 19.86 - 4.94
4. 82 – 67.18
5 Minute Check
Complete in your notebook.
Find each sum
1. 4.9 + 3.0
5 Minute Check
Complete in your notebook.
Find each sum
1. 4.9 + 3.0
4.9
+ 3.0
7.9
5 Minute Check
Complete in your notebook.
Find each sum
2. 0.796 + 13
5 Minute Check
Complete in your notebook.
Find each sum
2. 0.796 + 13
13.000
+ 0.796
13.796
We can annex zeros, if needed.
5 Minute Check
Complete in your notebook.
Find the difference.
3. 19.86 - 4.94
5 Minute Check
Complete in your notebook.
Find the difference.
3. 19.86 - 4.94
19.86
- 4.94
14.92
5 Minute Check
Complete in your notebook.
Find the difference.
4. 82 – 67.18
5 Minute Check
Complete in your notebook.
Find the difference.
4. 82 – 67.18
82.00
- 67.18
14.82
Annex zeros
Tuesday, Oct 8
Lesson 3.3
Multiplying Decimals by
Whole Numbers
Multiplying Decimals by
Whole Numbers
Objective: To understand how to multiply
decimals by whole numbers.
Multiplying Decimals by
Whole Numbers
At the end of this lesson you should be able
to answer the following question.
How can estimating products help place a
decimal correctly?
Multiplying Decimals by
Whole Numbers
To multiply a decimal and whole number,
multiply as normal and then place the
decimal point.
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .83.
First, round the numbers to the nearest whole
number to get an estimate.
What does .83 round to?
Digits from 0 to 4 round down and digits from
5-9 round up.
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .83.
First, round the numbers to the nearest whole
number to get an estimate.
What does .83 round to? 1
4 x 1 = 4, so
4 x .83 ≈ 4
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .83.
To multiply decimals.
Step 1 – Stack the numbers with the number
with the most digits on top.
.83
x 4
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .83.
To multiply decimals.
Step 2 – Multiply the digits.
.83
x 4
332
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .83.
To multiply decimals.
Step 3 – Determine the number of decimal
places in the factors to locate the decimal
place in the product.
.83
2 decimal places
x 4
3.32
2 decimal places
Is this a reasonable answer?
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .83.
Is this a reasonable answer?
3.32 ≈ 4
Multiplying Decimals by
Whole Numbers
Find the product of 3 and 14.2.
Estimate?
Multiplying Decimals by
Whole Numbers
Find the product of 3 and 14.2.
Estimate?
3 x 14 = 42
Step 1 - ?
Multiplying Decimals by
Whole Numbers
Find the product of 3 and 14.2.
3
x 14.2
Multiplying Decimals by
Whole Numbers
Find the product of 3 and 14.2.
14.2
x 3
Step 2 - ?
Multiplying Decimals by
Whole Numbers
Find the product of 3 and 14.2.
14.2
x 3
426
Step 3 - ?
Multiplying Decimals by
Whole Numbers
Find the product of 3 and 14.2.
14.2
x 3
42.6
1 decimal place
1 decimal place
Does this seem reasonable?
Multiplying Decimals by
Whole Numbers
Find the product of 3 and 14.2.
14.2
x 3
42.6
1 decimal place
1 decimal place
Does this seem reasonable?
42.6 ≈ 42
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .95.
(Do this on your own)
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .95.
Estimate ?
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .95.
Estimate ?
4x1=4
Actual product?
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .95.
.95
x4
3.80
2 decimal places
2 decimal places
Does this sound reasonable?
Multiplying Decimals by
Whole Numbers
Find the product of 4 and .95.
.95
x4
3.80
2 decimal places
2 decimal places
Does this sound reasonable?
3.8 ≈ 4
Multiplying Decimals by
Whole Numbers
Find the product of 2 and .018.
(Do this on your own)
Multiplying Decimals by
Whole Numbers
Find the product of 2 and .018.
Estimate?
Multiplying Decimals by
Whole Numbers
Find the product of 2 and .018.
Estimate?
2x0=0
Actual product?
Multiplying Decimals by
Whole Numbers
Find the product of 2 and .018.
.018
x 2
.036
3 decimal places
3 decimal places
Make sure you multiply the zeros. You may
need them later.
Multiplying Decimals by
Whole Numbers
Find the product of 2 and .018.
.018
x 2
.036
3 decimal places
3 decimal places
Does this sound reasonable?
Multiplying Decimals by
Whole Numbers
Find the product of 2 and .018.
.018
x 2
.036
3 decimal places
3 decimal places
Does this sound reasonable?
.036 ≈ 0
Multiplying Decimals by
Whole Numbers
Find the product of 4 and 0.0027.
(Do this on your own)
Multiplying Decimals by
Whole Numbers
Find the product of 4 and 0.0027.
Estimate?
Multiplying Decimals by
Whole Numbers
Find the product of 4 and 0.0027.
Estimate?
4x0=0
Actual product?
Multiplying Decimals by
Whole Numbers
Find the product of 4 and 0.0027.
0.0027
x 4
0.0108
4 decimal places
4 decimal places
Does this sound reasonable?
Multiplying Decimals by
Whole Numbers
Find the product of 4 and 0.012.
0.012
x 4
0.048
3 decimal places
3 decimal places
Does this sound reasonable?
0.0108 ≈ 0
Multiplying Decimals by
Whole Numbers
A sheet of printer paper is 8.5 inches by 11
inches. What is the area of the paper? (Hint:
area = length x width)
(Do this on your own)
Multiplying Decimals by
Whole Numbers
A sheet of printer paper is 8.5 inches by 11
inches. What is the area of the paper? (Hint:
area = length x width)
Estimate?
Multiplying Decimals by
Whole Numbers
A sheet of printer paper is 8.5 inches by 11
inches. What is the area of the paper? (Hint:
area = length x width)
Estimate?
9 x 11 = 99
Actual answer?
Multiplying Decimals by
Whole Numbers
A sheet of printer paper is 8.5 inches by 11
inches. What is the area of the paper? (Hint:
area = length x width)
8.5
x 11
85
+85 0
93.5
1 decimal place
1 decimal place
Is this a reasonable answer?
Multiplying Decimals by
Whole Numbers
A sheet of printer paper is 8.5 inches by 11
inches. What is the area of the paper? (Hint:
area = length x width)
8.5
x 11
85
+85 0
93.5
1 decimal place
1 decimal place
Is this a reasonable answer? 93.5 ≈ 99
Multiplying Decimals by
Whole Numbers
A batch of trail mix calls for 1.2 pounds of dry cereal. Kyle
is making 5 batches of trail mix. He already has 2 pounds
of dry cereal. How many more pounds of dry cereal does
he need?
(Do this on your own)
Multiplying Decimals by
Whole Numbers
A batch of trail mix calls for 1.2 pounds of dry cereal. Kyle
is making 5 batches of trail mix. He already has 2 pounds
of dry cereal. How many more pounds of dry cereal does
he need?
Estimate?
Multiplying Decimals by
Whole Numbers
A batch of trail mix calls for 1.2 pounds of dry cereal. Kyle
is making 5 batches of trail mix. He already has 2 pounds
of dry cereal. How many more pounds of dry cereal does
he need?
Estimate?
1x5=5
5–2=3
Actual answer?
Multiplying Decimals by
Whole Numbers
A batch of trail mix calls for 1.2 pounds of dry cereal. Kyle
is making 5 batches of trail mix. He already has 2 pounds
of dry cereal. How many more pounds of dry cereal does
he need?
1.2
x 5
6.0
1 decimal place
1 decimal place
6 lbs (what he needs) – 2 lbs (he has) = 4 lbs
Is this a reasonable answer?
Multiplying Decimals by
Whole Numbers
A batch of trail mix calls for 1.2 pounds of dry cereal. Kyle
is making 5 batches of trail mix. He already has 2 pounds
of dry cereal. How many more pounds of dry cereal does
he need?
1.2
x 5
6.0
1 decimal place
1 decimal place
6 lbs (what he needs) – 2 lbs (he has) = 4 lbs
Is this a reasonable answer? 4 ≈ 3
Multiplying Decimals by
Whole Numbers
Complete the Guided Practice on page 196.
When complete bring to the desk and show
Mr. Avery.
Agenda Notes
Homework –Homework Practice 3-3
Due Wednesday, Oct 9
Must show all work!
Mid-Chapter 3 Quiz –Thursday, Oct 10