Tiana's Percent Post

| Welcome to my percent post, friends.  |

Part 1 -  Understanding percents.

50% - Take the whole you have and divide it by 2 to get half, which is the same as 50%.
10% -  Take the whole and divide it by 10 to get 10% of the whole.
1% - Take the whole and divide it by 100, the number that you get is 1% of the whole.
25% - Take the whole and divide it by 4 to get 25% of your whole.

Percent -  A percent is a number out of 100 and is also another way of saying hundredths. ( eg. 21/100 is the same as 21% )

Part 2 - Representing Percents

180% -

12 3/4% -

0.7% -

Part 3 - Converting Decimals, Percents and Fractions

26%

• Decimal - Take the whole and divide it by 100. eg) 26 ÷ 100 = 0.26
• Fraction - To convert decimals to a fraction you need the decimal first. The digits that come after the decimal becomes your numerator.
  
  eg) 0.26 = 26/?
  
  After you've done that, you need to find out what place value the last digit of your decimal is in. That place value becomes your denominator.0.06
  
  eg) 0.26 → 0.06 | The 6 is in the hundredths place value, so your fraction would be 26/100

7/10

• Decimal - To convert a fraction to a decimal, you take the numerator [ 7 ], and divide it by the denominator [ 10 ]
  
  eg) 7 ÷ 10 = 0.7
• Percent - To convert a fraction to a percent, you firstly need to find the decimal, and then multiply by 100. Don't forget to add the percent symbol after it.
  
  eg) 7 ÷ 10 = 0.7
        0.7 × 100 = 70%

0.024

• Fraction - To convert a decimal to a fraction you need to find what place value the last digit of your decimal is in, which becomes your denominator. And then take away the zeros and decimals to make the digits after the decimal, your numerator.
  
  eg) 0.024 → 0.004 | The 4 is in the thousandths place value so your denominator would be ?/1000
  
  As for the numerator, take the digits that are after the decimal and it becomes your numerator.
  
  eg) 0.024 = 24/1000 is your fraction.
• Percent - To convert a decimal to a percent you multiply the whole by 100.
  
  eg) 0.024 × 100 = 2.4%

Part 4 - Percents of a Number

20% of 60

• Mental Math - To find out 20% of 60 using mental math, you can find out what 10 percent of 60 is and then multiply it by 2.
  
  eg) 10% of 60 = 6
        6 × 2 = 12 | 20% of 60 is 12.
• Calculator - To find 20% of 60 using a calculator you take your percent [20%], divide it by 100 and multiply it by the whole [60].
  
  eg) 20 ÷ 100 = 0.2
        0.2 × 60 = 12

0.1% of 40

• Mental Math - To find 0.1% of 40 you need to first find out 1% of 40, and then divide that number by 10. An alternative you can do is divide the whole by 1000, because to find 1% of a number, you divide by 100, so to find 0.1% you divide by 1000.
  
  eg) 40 ÷ 100 = 0.4
        0.4 ÷ 10 = 0.04 | 0.1% of 40 = 0.04
  
        ALTERNATIVE;
         40 ÷ 1000 - To do this mentally you can start from the right of the whole and move the decimal as many times as there of zeros within the number you're dividing it by. So for this question, you start from the right of the 40 and move the decimal 3 places to the left because there are 3 zeros in 1000.
  
  eg) 40 ÷ 1000 = 0.04

• Calculator - Using a calculator for this, all you need to do is divide 40 by 100 and divide it once again by 10 and it'll give you the answer right away. If you want a bit of a shortcut, another method you can use is dividing the whole by 1000.
  
  eg) 40 ÷ 100 = 0.4
        40 ÷ 10 = 0.04
                  OR
        40 ÷ 1000 = 0.04

250% of 400

• Mental Math - To find 250% of 400 with mental math, you can multiply 400 by 2 [ Because it is 200%] And then from the whole, you divide it by 2 / find the half and add it together, which is the same as getting 50%.
  
  eg) 2 × 400 = 800
        800 + 200 = 1000 [ 50% of 400 = 200 ]
        250% of 400 = 1000
• Calculator - To use a calculator all you have to do is divide the whole [ 400 ] by 100, and then multiply it by 250.
  
  eg) 400 ÷ 100 = 4
        4 × 250 = 1000

Part 5 - Combining Percents

Discount - A discount is when a price has been reduced / lowered from it's original value. The discount is usually a percent out of 100 in which the amount the percent is worth how much you are saving. 

Sale Price - A sale price is how much the item costs after the discount is taken off the original value. It will always be a lower value than the original price.

Total Price with Taxes - A total price with taxes is the amount you are paying after discounts are made and both GST and PST taxes are included. Taxes are always added whether there is a discount or not. [Taxes in Manitoba are 13%]

Question :

Store A: $326.78 [ 50% off once]

Store B: $326.78 [ 25% off first day, additional 25% off second day ]

Store A -
326.78 ÷ 100 = 3.2678
3.2678 × 50% = $163.39 - Final Price of 50% off
[ note; there's no need to subtract the 50% because since it's half, the difference is the same value ]
Store B -
326.78 ÷ 100 = 3.2678
3.2678 × 25% = 81.695
326.78 - 81.695 = 245.085 - Round off to $245.09 [ First day sale ]

245.085 ÷ 100 = 2.45085
2.45085 × 25 = 61.27125
245.085 - 61.27125 = 183.81375
Round off to $183.81 - Final Price of 25% off first day and additional 25% off second day.

Store A is the better buy, the reason is because reducing the price by 50% has a lower price value than 25% off an additional 25% off item. 50% is the same as having a half of one thing, if it's 50% of the price, then you only pay half of the price. With Store B, having 25% off one day, still has the price a bit high, and an additional 25% won't make the discount very significant. Although both stores have the same price of item, and the discounts match up [ 50% an 25% + 25% ]. Store A would be the way to go.

Also, another reason is because 50% off of one item has a different value than the method Store B used, because they started off with the same price but they discounted 25% and then another 25%. The second day discount does not apply to the original price, but instead of the discounted price, that's why the discounts from both store do not have the same value although they match up.

This is my percents post!