1. IGCSE1 CHAPTER5 Vivian

2. Chapter5: Fractions----percentages Percentages:  A percentage is a fraction whose denominator is 100  To convert a fraction into a percentage, we can multiply 100 to both denominator and numerator and then cancel. eg. 8/15=

3. Chapter5: Fractions---- percentages Practice: fraction decimal 2.5 percentage 0.833 83.3% 250% 0.075 0.32 32% 2.5 250% 0.333

4. Chapter5: Fractions----percentages Percentages of a given quantity 1. change the percentage into a fraction 2. multiply the fraction by the given number and simplify A is 60% of B. B is 5. Solve A.

5. Chapter5: Fractions----percentages Eg1. 5% of 600

6. Chapter5: Fractions----percentages Finding a number as a percentage of another:  First, to write the first number as a fraction of the second number;  Then multiplied by 100.  Then add a percentage sign. eg. Express 16 as a percentage of 48. = =

7. Chapter5: Fractions----percentages Try by yourself: 1.Express 14 as a percentage of 35 2.Express 3.5 as a percentage of 14 3.Express 1.3 as a percentage of 5.2 4.36 people live in a block of flats. 28 of these jog around the park each morning. What percentage of people living in the block of flats go jogging around the park? 40% 25% 77.8%

8. Chapter5: Fractions----percentages Now come to some examples harder 1. A can of fruit has a mass of 530g. The fruit has a mass of 500g. Find the mass of the fruit as a percentage of the total mass.

9. Chapter5: Fractions----percentages 2. During the first week of October, a bookshop sold 880 books. In the second week, it sold 15% fewer books. How many books did it sell in the second week? 880×(1-15%)=748

10. Chapter5: Fractions----percentages

11. Chapter5: Fractions----percentages Example 1. A shop keeper buys an article for $500 and sells it for $600. What is the percentage profit?

12. Chapter5: Fractions ----percentages Example A person buys a car for $16000 and sells it for $12000. Calculate the percentage loss.

13. Try: A pair of shoes were sold for $63. The pair of shoes were discounted by 30%. What was the original price of shoes before the sale?

14. Group work For percentages section, in groups, select 10 questions for students in other groups. Evaluation: 1. the base point of each group is 10. 2. if your answer is right, +1 3. if the student cannot answer your question, +1 4. group star for sun, sun for heart, heart for star 5. you can call anyone in target group to solve your question 6. each student answer at least one question

15. HW: WORKSHEET

16. Thank you!