Chapter 4 Notes
Key words: percent, fractional percent, combined percents
Percent means parts per 100-- the symbol is %
Percent means out of 100
It is another name for hundredths
100% is equivalent to one whole
Example: 65% means 65 out of 100 or 65/100 or 0.65
A fractional percent is a percent that includes a portion of a percent. E.g. ½%
0.42%, 7 3/8%, 4.5%
-------------------------A hundreds grid is a great way to show percent:
--------------------------
--------------------------
-------------------------------------------------------To convert fractions to decimals…
Divide the numerator by the denominator
9/20 = 9
20 = 0.45
------------------------------------------------------Converting Decimals to Percents
Let’s convert 0.05 to a percent
Recall decimal to percent:
move the decimal to the right two (2) places and add a percent (%) sign
0.05 = 5% OR multiply the decimal by 100
0.05 x 100 = 5%
To convert decimals to percents…
multiply by 100
0.45 x 100 = 45%
-------------------------Convert percents to decimal
To change a percent to a decimal… divide by 100
If the percent is in fraction form, change the fraction to a decimal then divide by
100
--------------------------
Convert percents to fractions
• Change the percent to a decimal
• Determine the place value of the last digit and place the number over this
place value
• How can you express this percent as a fraction?
The last digit is the 8 and it is in the hundredths place so
-------------------------•
•
•
•
•
Halve means to divide by two.
Double means to multiply by two.
In math, the word of often means to multiply.
You can combine percents by adding individual percents together.
A repeating decimal contains a digit or group of digits that repeat forever. You can write a
repeating decimal using bar notation. That is, a bar over top of the number or numbers that
repeat.
0.333 33… =0.3
0.454545… = 0.45
My Notes
Percent Circles
Name: _______________________________
Date: ________________________
.…MASTER 14.…
Fraction Circles
1
2
1
3
1
4
1
5
1
6
1
8
1
10
1
12
Copyright © McGraw-Hill Ryerson, 2006
Name: _______________________________
Date: ________________________
.…MASTER 15.…
Fraction Strips
1
2
1
3
1
4
1
5
1
6
1
8
1
10
1
12
Copyright © McGraw-Hill Ryerson, 2006
Name: _______________________________
Date: ________________________
.…MASTER 11.…
Hundred Chart
Copyright © McGraw-Hill Ryerson, 2006
10 × 10 Grids
NAME ___________________________
© 2008 National Council of Teachers of Mathematics
http://illuminations.nctm.org