Percentages Teaching Material
Instruction
It is important to have a solid background in decimals and fractions before you try to handle percentage questions. Percentages are simply fractions. Per means "out of" and cent means "a hundred". Percentages are fractions with 100 as a denominator. They are often noted with this sign: %.
| 10% | means 10 out of 100 or |
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| 13% | means 13 out of 100 or |
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| 100% | means 100 out of 100 or |
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100% means everything. 100% of your salary is your whole salary. You simply follow the same rules of conversion from fractions to decimals for calculating percentages. Simply move the decimal points two places to the left to convert percents to decimals. This is essentially dividing the percentage by 100.
Any percent larger than 100% indicates more than the whole. For example:
A man’s stock portfolio is worth 125% of what it was a year ago. This means that the stocks are now worth 25% more. If his stocks were worth $500 last year, they would be worth:
$500 x 125% =
| $500 | |
| x | $1.25 |
| $625 | |
Percentages with Fractions
Some questions you encounter may incorporate percentages and fractions. Examples include 2 1/2 % or 33 1/3 %. In order to deal with these problems, you must first convert the percentages to improper fractions.
| 2 1/2 = 5 / 2 | 33 1/3 = 100 / 3 |
After this step you simply carry out the division question.
Once you have the decimal equivalent of the percentage, you then follow the same rules that apply to a regular percentage. Divide the number by 100, or more simply, move the decimal to the left twice. Thus:
| 2 1/2% = 0.025 | 33 1/3% = 0.3333 |
Percentages You Should Memorize
| 25% | = | 1 / 4 | = | 0.25 |
| 50% | = | 1 / 2 | = | 0.5 |
| 75% | = | 3 / 4 | = | 0.75 |
| 100% | = | 4 / 4 | = | 1.00 |
| 33 1/3% | = | 1 / 3 | = | 0.333 |
| 66 2/3% | = | 2 / 3 | = | 0.666 |
| 10% | = | 1 / 10 | = | 0.1 |
| 20% | = | 1 / 5 | = | 0.2 |
| 40% | = | 2 / 5 | = | 0.4 |
| 60% | = | 3 / 5 | = | 0.6 |
| 80% | = | 4 / 5 | = | 0.8 |
Peer Support
If you are having difficulty with the subject matter, there is always a great deal of support available to you from other members through the Forum. Simply do a search for the material you need help with (math, algebra, integers, etc.) Members are very supportive and helpful. Don't hesitate to post any questions, or provide answers to others seeking assistance.
Percentage Practice Tests
Work through the following tests to make sure you are comfortable with the material.
