Licensing information

1
Licensing information

• Users should treat this material as a working
  draft. This material can be used in its current
  form, customized, and/or printed or displayed by
  the user.
• The author(s) request feedback on all materials
  so that they can be continually improved and
  updated.
• This material is licensed under the Creative
  Commons Attribution-Share Alike license
  (http//creativecommons.org/licenses/by-sa/3.0/).
• Author Kevin Hall
• Wording for the legal statement above is adapted
  from the legal statement for Trigonometry,
  published in 2009 by The CK-12 Foundation
  http//about.ck12.org/

2
Teaching notes

• Before getting to class, be sure to print out the
  answers and have them handy. While students are
  practicing the drill questions, you want to be
  walking around praising and prompting them, not
  trying to solve the questions for yourself.
• On the drill slides, 4 questions come up at a
  time. Its ok if some students only do the first
  couple, as long as they get them right.
• Again, these are designed to let you walk around
  the room and see how students are doing while the
  classes discusses and/or practices.

3
Trayon took 25 total shots, and made 18 of them.
What percent did he make?
You figure out that you like about 4 out of every
9 songs that you hear on your WJLB. At that
rate, if you hear 54 songs, how many will you
like?
1).
2).
100
out of
18 4
72
6
??
Copy _____ times
6
24
18
18 made
18
18
18
x
you like
x
shots made
you like
4

total
total
54
9

6
??
6
??
Copy _____ times
_____ total shots
25 total shots
25
25
25
25
100
Copy _____ times
4
??
At that rate, out of 54 songs, youll like
Answer
24.
Answer
4
Solving Proportions with Equivalent Fractions
5
25
5
Step 1 Copy Problem.
Step 2 What is it multiplied by?
Step 3 Multiply numerator and denominator
Step 4 Calculate answer.
3).
4).
5).
6).
2
30
56
99
5
7).
8).
9).
10).
40

35
72
15
11).
12).
13).
14).
49
72
100
45
Two 20s, plus a quarter of 20, is 45.
6
Divide and Conquer
In high school, we often use the fraction bar,
not the dividing sign.
The biggest problem people have with dividing
is knowing which number to write first.
21 3 is not the same as 3 21.
is not the same as
Compare them with a calculator
7
0.143
0.142857
Rounded
Not even close!
7
A Picture for Dividing
What does dividing do?
Dividing splits up an amount into equal parts.
Draw a picture to represent 1 5
.2
Split up 1
1
1 5 means you have ___ , and youre splitting
it into ____ pieces.
.2
5
.2
It adds up to 1
.2
1 5
.2
.2
5 pieces
8
A Real-Life Example
SCENARIO For 2.60, you can buy 4 songs
online. What is the price per song?
15). Why do we DIVIDE to answer this?
How would you explain it?
Were splitting up a total into 4 parts.
0.65
16). What expression shows the answer?
Total 2.60
0.65
2.60 4
???
or
4 2.60
0.65
??
Please explain your thinking

0.65
0.65
Were dividing it into 4 pieces,
1 song
4 songs
so
we divide BY 4.
What we know
Want to find out
17). Please write the answer as a
fraction and a decimal.
0.65 /song