Concept 1-Converting between fractions, decimals, and percents
Watch these videos to help with the conversions!
Click here to see how to convert!
Here is a video of the "non-dollar" conversions
Here is some more practice!
Fraction
|
Decimal
|
Percent
|
0.2
|
||
75%
|
||
3/20
|
||
62.4%
|
||
0.384
|
Concept 2- The Percent Bar Model
This model is helpful for the visual learners. The whole idea behind the percent bar model is to be able to find the percent of some number. remember that some big benchmark percents to look for are 50%, 10%, 5%, and 1%. You can pretty much combine these to do any percent of a number!
Practice:
- What is 20% of 45?
- What is 33.3% of 36?
- What is 85% of 60? (Hint use your knowledge of what 50%, 10% and 5% are!)
Answers to Practice to check yourself on:
- 9
- 12
- 51
Concept 3- The Proportions Model
This model is helpful for the people who really like straight forward multiplication and division. Use the following formula to help you remember how to set it up.
part = ?%
whole 100%
When reading the question, it is helpful to identify and label so that when you set it up, you have everything in the right place. For example:
Ashley had a box with 30 cookies. She ate 10% of them. How many cookies did she eat?
- in this question, the 30 is the whole and the the 10% goes with the ?%
1. After you have identify each number is, you can set up the proportion.
x = 10%
30 100%
2. Now reduce the known ratio by simplifying.
x = 1%
30 10%
3. Re-write your proportion with the known ratio first.
1% = x
10% 30
4. Find your scale factor.
1% x 3= x
10% x 3 30
5. Solve
x = 3 cookies
Practice:
- If 8 out of 20 students in a class are boys, what percent of the class is made up of boys?
- 18 is 40% of what number?
- What is 20% of 45?
- What is 25% of 52?
- What percent of 56 is 14?
Once you work through them, go check your answers HERE! Just look at the line that says "solution.
Concept 4- Discounts (Percent of Decrease)
Who doesn't like a discount?! I'm all about saving money! So think about when you go into a store and the shirt that you really want is 25% off. What a great feeling right?! Does that mean that you only pay 25% of the cost though? NOPE! If I am looking at the shirt and it is $20, I know that I'm going to be able to SUBTRACT a few dollars from that $20 price. Now let's figure out the total after the discount!
1. Identify what each number is and set up the proportion.
$20 is the WHOLE price, so it is my whole. 25% off is my ?%.
x = 25%
$20 100%
2. Reduce the known ratio.
x = 1%
$20 4%
3. Re-write your proportion with the known ratio first.
1% = x
4% $20
4. Find your scale factor.
1% x 5 = x
4% x 5 $20
5. Solve.
x = $5
YOU AREN'T DONE THOUGH! You found out how much you get to subtract, but that doesn't tell you the TOTAL.
Whole - Discount = Total $20 - $5 = $15
Concept 5- Tax and Tip (Percent of Increase)
Except for one weekend a year, when you go to buy something at the mall, you don't get to pay the price on the tag. Your jeans may be $30, but when you get up to the register, you have to pay tax on those jeans. This means you have to pay and ADDITIONAL amount of money. If the tax rate is 10%, how much will you pay total?
1. Identify what each number is and set up the proportion.
$30 is the WHOLE price, so it is my whole. 10% tax is my ?%.
x = 10%
$30 100%
2. Reduce the known ratio.
x = 1%
$30 10%
3. Re-write your proportion with the known ratio first.
1% = x
10% $30
4. Find your scale factor.
1% x 3 = x
10% x 3 $30
5. Solve.
x = $3
YOU AREN'T DONE THOUGH! You found out how much extra you have to pay for the tax, but that doesn't tell you the TOTAL.
Whole + Tax (or tip) = Total $30 + $3 = $33
Practice for Discount, Tax, and Tip is HERE!
If you are feeling like you need any more practice, you can go HERE and practice all of the concepts! Have a great weekend and good luck on the final!
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