Percentages · Grade 8
In Percentages (Grade 8) you practise 4 skills: A percentage of an amount, and a part as a percentage · Percentage increase and decrease · Comparing percentages · Percentage word problems. Percent means out of a hundred. 25% is 25/100, which is a quarter. To find 25% of 200, split 200 into four equal parts: each part is 50.
After an increase of 20%, the new price is 120% of the old price, so you multiply by 1.2. With 20% off, you pay 80% of the price, so you multiply by 0.8. When there are two changes one after the other, the second change is worked out from the new amount. An increase of 10% followed by a decrease of 10% does not take you back to the starting price: from 100 you go up to 110, then down to 99. To find the price before a change, write an equation. If you pay 80 after 20% off, then the price times 0.8 equals 80, so the price is 100.
Tip: If you are not sure, suppose the amount at the start is 100: then it is easy to see what it is now.
What you learn
A percentage of an amount, and a part as a percentage
For example: What is 10% of 390?
Answer and solution
The answer: 39
10% = 1/10 390 ÷ 10 = 39 10% of 390 is 39.
Percentage increase and decrease
For example: A hat cost 80 shekels, and its price went up by 5%. What is the new price?
Answer and solution
The answer: 84 shekels
The increase is 5% of 80: 5% = 1/20 80 ÷ 20 = 4 80 + 4 = 84 The new price is 84 shekels.
Comparing percentages
For example: Which is greater: 75% of 100, or 10% of 180?
- The second is greater
- They are equal
- The first is greater
Answer and solution
The answer: The first is greater
75% of 100: 75% = 3/4 100 ÷ 4 = 25 25 × 3 = 75 10% of 180: 10% = 1/10 180 ÷ 10 = 18 75 is greater than 18, so the first is greater.
Percentage word problems
For example: The price of a cinema ticket went up by 50%, and a ticket now costs 72 shekels. What was the price before the increase?
Answer and solution
The answer: 48 shekels
An increase of 50% means multiplying by 1.5. Call the old price x and write an equation: 1.5x = 72 Divide both sides by 1.5: x = 72 ÷ 1.5 = 48 The old price was 48 shekels.
The exercises are made by rules and the answers are worked out in code, so there are new exercises every time. The topic follows the Israeli Ministry of Education's grade 8 transition maths curriculum (2026–27).