5 Minute Check Complete in your notebook. Estimate each
product. 1. 9.7 x 3 2. 3.4 x 5 3. 17.5 x 8 Multiply. 4. 1.5 x 6 5.
3.1 x 13 6. 3.48 x 25
Slide 2
5 Minute Check Complete in your notebook. Estimate each
product. 1. 9.7 x 3
Slide 3
5 Minute Check Complete in your notebook. Estimate each
product. 1. 9.7 x 3 10 x 3 = 30
Slide 4
5 Minute Check Complete in your notebook. Estimate each
product. 2. 3.4 x 5
Slide 5
5 Minute Check Complete in your notebook. Estimate each
product. 2. 3.4 x 5 3 x 5 = 15
Slide 6
5 Minute Check Complete in your notebook. Estimate each
product. 3. 17.5 x 8
Slide 7
5 Minute Check Complete in your notebook. Estimate each
product. 3. 17.5 x 8 18 x 8 = 144
Slide 8
5 Minute Check Complete in your notebook. Multiply. 4. 1.5 x
6
Slide 9
5 Minute Check Complete in your notebook. Multiply. 4. 1.5 x 6
1.51 decimal place x 6 9.01 decimal place
Slide 10
5 Minute Check Complete in your notebook. Multiply. 5. 3.1 x
13
Slide 11
5 Minute Check Complete in your notebook. Multiply. 5. 3.1 x 13
3.11 decimal place x 1 3 Dont forget the zero 93 + 310 40.31
decimal place
Slide 12
5 Minute Check Complete in your notebook. Multiply. 6. 3.48 x
25
Slide 13
5 Minute Check Complete in your notebook. Multiply. 6. 3.48 x
25 3.482 decimal places x 25 Dont forget the zero 1740 + 6960
87.002 decimal places
Slide 14
Flashcards!
Slide 15
Wednesday, Oct 9 Lesson 3.2 and 3.4 Multiplying Decimals by
Decimals
Slide 16
Objective: To understand how to estimate and multiply decimals
by decimals.
Slide 17
Multiplying Decimals by Decimals At the end of this lesson you
should be able to answer the following questions. How do you
determine which place value to use when multiplying decimals by
decimals? Why is estimating not as helpful when multiplying very
small numbers?
Slide 18
Multiplying Decimals by Decimals To multiply decimals, multiply
as normal and then place the decimal point.
Slide 19
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. First round the numbers to the nearest whole number to get an
estimate. What does 8.7 round to? Digits from 0 to 4 round down and
digits from 5-9 round up.
Slide 20
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. First round the numbers to the nearest whole number to get an
estimate. What does 8.7 round to? 9 What does 2.8 round to?
Slide 21
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. First round the numbers to the nearest whole number to get an
estimate. What does 8.7 round to? 9 What does 2.8 round to? 3
Slide 22
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. First round the numbers to the nearest whole number to get an
estimate. 9 x 3 = 27, so 8.7 x 2.8 27
Slide 23
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. To multiply decimals. Step 1 Stack the numbers with the number
with the most digits on top. 8.7 x 2.8 (Since both numbers have 2
digits, either could be on top )
Slide 24
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. To multiply decimals. Step 2 Multiply the digits. 8.7 x 2.8
696 Dont forget to add the zero. +1740 2436
Slide 25
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. To multiply decimals. Step 3 Determine the number of decimal
places in the factors to locate the decimal place in the product.
8.7 1 decimal place x 2.8 + 1 decimal place 696 +1740 24.36 2
decimal places
Slide 26
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. 8.7 x 2.8 696 +1740 24.36 Is this a reasonable answer?
Slide 27
Multiplying Decimals by Decimals Find the product of 8.7 and
2.8. Is this a reasonable answer? 24.35 27
Slide 28
Multiplying Decimals by Decimals Find the product of.98 and 7.3
Estimate?
Slide 29
Multiplying Decimals by Decimals Find the product of.98 and 7.3
Estimate? 1 x 7 = 7, so.98 x 7.3 7 Next?
Slide 30
Multiplying Decimals by Decimals Find the product of.98 and
7.3.98 x 7.3 Next?
Slide 31
Multiplying Decimals by Decimals Find the product of.98 and
7.3.98 x 7.3 294 Dont forget to add a zero +6860 7154 Next?
Slide 32
Multiplying Decimals by Decimals Find the product of.98 and
7.3.98 2 decimal places x 7.3 +1 decimal place 294 +6860 7.154 3
decimal places Is this a reasonable answer?
Slide 33
Multiplying Decimals by Decimals Find the product of.98 and
7.3.98 2 decimal places x 7.3 +1 decimal place 294 +6860 7.154 3
decimal places Is this a reasonable answer? 7.154 7
Slide 34
Multiplying Decimals by Decimals Find the product of 3.6 and
0.05. Estimate?
Slide 35
Multiplying Decimals by Decimals Find the product of 3.6 and
0.05. 4 x 0 = 0, so 3.6 x 0.05 0
Slide 36
Multiplying Decimals by Decimals Find the product of 3.6 and
0.05. 4 x 0 = 4, so 3.6 x 0.05 0 Actual product?
Slide 37
Multiplying Decimals by Decimals Find the product of 3.6 and
0.05 0.05 2 decimal places x 3.6 +1 decimal place 0030 + 0015 0.045
3 decimal places Is this a reasonable answer?
Slide 38
Multiplying Decimals by Decimals Find the product of 3.6 and
0.05 0.05 2 decimal places x 3.6 +1 decimal place 030 +0150 0.180 3
decimal places Is this a reasonable answer? 0.180 0
Slide 39
Multiplying Decimals by Decimals Find the product of 0.112 and
7.2 Estimate?
Slide 40
Multiplying Decimals by Decimals Find the product of 0.112 and
7.2 Estimate? 0 x 7 = 0, so 0.112 x 7.2 0 Actual product?
Slide 41
Multiplying Decimals by Decimals Find the product of 0.112 and
7.2 0.112 3 decimal places x 7.2 +1 decimal place 0224 +07840.8064
4 decimal places Is this a reasonable answer?
Slide 42
Multiplying Decimals by Decimals Find the product of 0.112 and
7.2 0.112 3 decimal places x 7.2 +1 decimal place 0224 +07840.8064
4 decimal places Is this a reasonable answer? 0.8064 0
Slide 43
Multiplying Decimals by Decimals Find the product of 1.4 and
0.067 Estimate?
Slide 44
Multiplying Decimals by Decimals Find the product of 1.4 and
0.067 Estimate? 1 x 0 = 0 1.4 x 0.067 0 Actual product?
Slide 45
Multiplying Decimals by Decimals Find the product of 1.4 and
0.067 0.067 3 decimal places x 1.4 +1 decimal place 0268 +00670
0.0938 4 decimal places Is this a reasonable answer?
Slide 46
Multiplying Decimals by Decimals Find the product of 1.4 and
0.067 0.067 3 decimal places x 1.4 +1 decimal place 0268 +00670
0.0938 4 decimal places Is this a reasonable answer? 0.0938 0
Slide 47
Multiplying Decimals by Decimals Mr. Averys car can travel
28.45 miles on one gallon of gas. If his gas tank holds 11.5
gallons, how far can he travel on one tank? Estimate?
Slide 48
Multiplying Decimals by Decimals Mr. Averys car can travel
28.45 miles on one gallon of gas. If his gas tank holds 11.5
gallons, how far can he travel on one tank? Estimate? 28 x 12 = 336
Keep in mind 28 x 12 = 28 x 10 + 28 x 2 = 280 + 56 = 336 Actual
product?
Slide 49
Multiplying Decimals by Decimals Mr. Averys car can travel
28.45 miles on one gallon of gas. If his gas tank holds 11.5
gallons, how far can he travel on one tank? 28.45 2 decimal places
x 11.5 +1 decimal place 14225 28450 +284500 327.175 3 decimal
places Is this a reasonable answer?
Slide 50
Multiplying Decimals by Decimals Mr. Averys car can travel
28.45 miles on one gallon of gas. If his gas tank holds 11.5
gallons, how far can he travel on one tank? 28.45 2 decimal places
x 11.5 +1 decimal place 14225 28450 +284500 327.175 3 decimal
places Is this a reasonable answer? 327.175 336
Slide 51
Multiplying Decimals by Decimals Determine whether the
following statement is always, sometimes or never true. The product
of two decimals less than 1 is less than either of the factors.
Give examples to support your answer.
Slide 52
Multiplying Decimals by Decimals Determine whether the
following statement is always, sometimes or never true. The product
of two decimals less than 1 is less than either of the factors.
Always. 0.3 x 0.5 =.15, which is less than 0.3 and 0.5 0.75 x 0.6 =
0.45
Slide 53
Multiplying Decimals by Decimals Complete the Mid-Chapter Check
on page 214. When complete bring to the desk and show Mr. Avery.
Agenda Notes Homework Homework Practice 3-2/3-4 Due Thursday, Oct
10 Mid-Chapter 3 Quiz Thursday, Oct 10