Presentation on theme: "Extending Hot Shots I am learning to solve different kinds of percentage problems. Percentage unknown e.g. Tim scored 25 out of 30 in a test what percentage."— Presentation transcript:
Extending Hot Shots I am learning to solve different kinds of percentage problems. Percentage unknown e.g. Tim scored 25 out of 30 in a test what percentage did he get correct? = ?% Part unknown e.g. Susan completed a test with 35 questions. She scored 60%. How many questions did she get correct? = 60% Whole unknown e.g. Blake answered 20 questions correctly in a test. That was a score of 80%. How many questions were in the test? = 80% Do not start this lesson unless you have an excellent understanding of Hot Shots.
Percentage unknown Alice answered 32 quiz questions and got 24 correct. What percentage did she answer correctly? We can display this question on a number line. 0 0 100% 32 24 ? We could divide 100 by 32. This would tell us what percentage each question is worth. 100 ÷ 32 = 3.125 Use a calculator to help you with the division in this question. Each mark is worth 3.125% and Alice answered 24 questions so… 24 X 3.125 = 75% 75% Or we could….Divide 24 by 32.24 ÷ 32 = ? This gives us the percentage as a decimal. 0.75 Questions Answers
Part unknown Zoe answered 45 quiz questions and got 80% correct. How many questions did she get correct? We can display this question on a number line. 0 0 100% 45 ? We could divide 45 by 100. This would tell us what mark each percentage is worth. 45 ÷ 100 = 0.45 Use a calculator to help you with the division in this question. Each percentage is worth 0.45 and Alice answered 80% correctly. 80 X 0.45 = 36 80% Or we could work out 80% of 45….80% is the same as 0.8 Questions Answers So… 0.8 X 45 = ? 36
Whole unknown Stacey answered 72 quiz questions correctly which was 90% correct. How many questions were there? We can display this question on a number line. 0 0 100% ? Use a calculator to help you with the division in this question. 90% Questions Answers 72 We could divide 72 by 90. This works out how much of a mark each percentage is. 72 ÷ 90 = ? 0.8 Each mark is worth 0.8 of a percentage. 100% is every question so…100 X 0.8 = 80 Note: Whole unknown questions are much more difficult than the other two types of questions we have looked at.
Now try these questions on your own. Click again when you have worked out all your answers. Need some more practise? Try Teacher Tools Fractions, Decimals and Percentages Book Numeracy resourcesNumeracy resources You may use a calculator to help you answer the following questions. 1) Tim threw a cricket ball at a wicket 25 times. He hit it 10 times. What percentage of the time did he hit the wicket? 2) Allan ate 75 pieces of fruit. 20% of these were bananas. How many bananas did he eat? 40% 15%