2. Fractions, Decimals & Percentages
Week 04:
Fractions, Decimals & Percentages
Calculating fraction parts
Calculating percentage parts
Using fractions and percentages to calculate increases and decreases when using money
Converting between fractions, decimals and percentages
Calculating and using equivalent fractions, decimals and percentages

3. What did we do last week?

4. Key Terminology anrctifo rceeepntag cedmali nuatorrme danmintoore
queivantel
fyimplis
cireasen
cereased
allccuate
Fraction
Percentage
Decimal
Numerator
Denominator
Equivalent
Simplify
Increase
Decrease
Calculate

5. Converting Fractions, Decimals & Percentages
Fraction to Decimal: numerator ÷ denominator
Decimal to Percentage: x 100
Percentage to Fraction: percentage becomes numerator, denominator is 100. Simplify.
Fraction
Percentage
Decimal

6. Complete these FDP conversions…

8. ¼ Fractions Denominator: The total number of parts
Numerator: The number of parts we are interested in

9. What is ¼ of 12?

10. Divide by the bottom number, multiply by the top
Finding a fraction
Calculate ¾ of 500.
Divide by the denominator (bottom number) to get the value of ¼:
500  4 = 125
Multiply by the numerator (top number) to get the answer:
125 x 3 = 375
Divide by the bottom number, multiply by the top

11. Practice
3/8 of 32
½ of 24
2/5 of 20
6/7 of 14

12. Exam question
A £45 pair of jeans have 1/3 off the price in a sale. What is the sale price?
Original Price: £45
1/3: 45 ÷ 3 = £15
New Price: £45 - £15 = £30
The sale price of the jeans is £30.

13. Equivalent fractions

14. Making fractions
Fractions are sometimes hidden in words instead of numbers:
60 learners were questioned in a recent survey and 15 were found to be smokers.
Where’s the fraction?
The total number = 60, the amount that were smokers = 15
= 15/60.
Can the fraction be simplified? Yes! ¼
The survey found a quarter of learners smoked.

15. Making fractions
Santander recently conducted a survey on their customers:
200 are years old
400 are years old
700 are years old
900 are years old
300 are 65+ years old
What is the fraction of people between 19 and 39?
1300/2500
What is this fraction when simplified?
13/25

16. Percentage of an amount
Use the percentage button on your calculator!
What is 20% of 500?
Type in 500 x 20% =
You should get the answer 100.
Alternative:
Percent means ‘out of 100’, so divide by 100 then multiply by the percentage you are looking for:
÷ 100 = 5
5 x 20 = 100.

17. Percentage of an amount

18. Percentage increase and decrease
Work out the percentages as before. Increase means ‘add on to’ and decrease means ‘take away from’:
Account Holder
2016 Balance
% Change
2017 Balance
H. Solo
£5, 102
10% increase
K. Broflovski
£80, 980
30% decrease
S. Smith
£32, 654
5% increase
J. T. Kirk
£200, 902
10% decrease
£5,
£56, 686
£34,
£180,