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September 09, 2011
If one advances confidently in the
directions of his dreams, and
endeavors to live the life which he
has imagined, he will meet with a
success unexpected in common
hours.
-- Henry David Thoreau
September 09, 2011
Challenge Problem:
Elizabeth calls two members of her
softball team to schedule a practice. Each
of those team members calls three other
team members. Then, each of those
members calls two more members. How
many team members are called? Do not
count Elizabeth.
September 09, 2011
September 09, 2011
Review: Estimate each quotient using
compatible numbers.
1. 24.8 ÷ 4.9
2. 103.8 ÷ 13.2
3. 128.62 ÷ 9.86
4. 41.77 ÷ 6.07
September 09, 2011
Vocabulary:
-Identity Property of Multiplication : The product of 1 and a number
is that number
ex) 1 x 5 = 5
1xa=a
-Zero Property : Product of 0 and any number is 0
ex) 5 x 0 = 0
ax0=0
-Commutative Property of Multiplication : Changing the order of
factors does not change the product.
ex) 2 x 3 = 3 x 2
-Associative Property of Multiplication : Changing groupings of
factors does not change the product
ex) (2 x 3) x 4 = 2 x (3 x 4)
6x4
2 x 12
24
24
What is the missing number? Which property is shown?
39.) 3.6 x _____ = 0
40.) ______ x 1 = 25.5
41.) ______ x 4 = 4 x 3
42.) (2.5 x ____ ) x 2.3 = 2.5 x (1.4 x 2.3)
-
September 09, 2011
Objectives:
1. Multiply decimals
2. Divide decimals
September 09, 2011
Multiplying:
0.2 x 0.7
Step 1: Multiply the numbers as whole numbers
2x7=
Step 2: Locate the number of decimals in the original
problem. That will be the how many numbers you will
have behind the decimal point in your answer!
3.) 0.3 x 0.5
5.) 8.7 x 0.45
September 09, 2011
Dividing Decimals:
Step 1: Rewrite the divisor as a whole number
***Remember to multiply the divisor and dividend by
the same power of 10***
17.) 1.89
25.)
5.103
0.72
0.054
19.) 8.9
27.)
186.9
0.8
592
September 09, 2011
Question: Can you divide by zero?
Hint: Look at these similar problems to help
you decide:
a) 6 ÷ 3 = 2
b) 6 ÷ 0 = ___
3x2=6
0 x ___ = 6
Answer: There is no value for the __ in the
above problem. Division by zero is undefined,
so you can't do it.
September 09, 2011
1. In your notebooks, explain how to multiply
and divide by decimals.
2. Quiz
3. Classwork/Homework:
Pg. 20-22: 2-20 (skip 10-14) Evens
Only, 70-77 All