Percentages Flashcards
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Ratio to find all percentages
What is the Top Left Number
What is the Bottom Left Number
Top Right Number
Bottom Right Number
Top Left: Percentage
Bottom Left: 100
Top Right: Portion of the Whole
Bottom Right: The Whole Number
Formula for Percentage Change:
New number, Minus, Old number ,Divided by Old Number, Multipled by 100
Formula to convert Decmil to Percent
Move decmil over to the Right 2 places
( Make it Larger )
Or
Multiple by 100
Formula to convert Fraction to Percentage
Divide Top Number by Bottom Number
Multiply by 100
How do you convert Repeating decmils to fractions.
Examples
Put the repeating part over 9 followed by as many 9s as the repeating part
- THE NUMBERS BELOW ARE ALL REPEATING
.4 = 4/9
.35 = 36/99
.420 = 420/999
To get a Fraction from a Decmil with only a part of it repeating. Describe the Method
How do you confirm if you have the correct fraction?
Subtract the repating part from the non reating part but Move the repeating part to make it start a new decmil itself.
Take Subtracted Total and Repeating total and Change them to Decmils.(Remember Repeating Decmils go over 9(s) the same amount as the number of digits as the number.)
Add the decmils together ( Always Reduce )
To Confirm: Divide Top Number of Fraction by Bottom Number
Formula for finding New or Original Price with a Percentage involved.
Exp. Sneakers cost 133.75$ with a 7% Sales Tax.
What is the Original Price of the Sneakers
New = Original × (1 + or - Rate[Percentage as a Decmil] )
- 75 (New) = Original [X] × (1 + 0.07 [Rate])
- 75 = [X] × 1.07 Algebra Do the Opposite to get X alone. Divide both sides by 1.07
- 75 ÷ 1.07 = 125
Formula to Add ANY% to a number..
EXP.
Shoes cost 299$ what is the total with a 6% Sales tax?
Set up a proportion with
299 on bottom right
Formula to find Original Value when taxes are already included.
Exp.
Karen pays a total of 69.55 for a shirt with a 7% Sales Tax included. What is the Original price of the shirt.
New value 69.55 ÷ 1 + ( Percentage in Decmil form)
69.55 ÷ 1.07 = 65
Formula to find the Oringal Value when the Percentage Decrease has already been added.
Exp.
Karen pays 69.55$ for a shirt with a 7% discount already applied.
What is the Original Price of the shirt?
New Price 69.55 ÷ 1 - ( Percentage as a Decmil .07)
69.55 ÷ .93 = 74.78