Presenting information

Try This - Working with percentages

Tables often use percentages, rather than actual numbers, to compare the number of people using things for different purposes. Numbers are expressed as if they are ‘out of a hundred’ when using percentages, which makes it easier to compare different values. You can recognise percentages by the % symbol. As you can see from halfway down Table 1 in the last activity, 50% of the people who had used the internet in the previous 3 months used it for buying or ordering things. (They may also have used it for other purposes.)

How many people is that? Obviously, that would depend on the total number of people. For argument's sake, we will say that 100 people in total had used the internet in the previous three months. That's relatively easy to work out: 50% of 100 is 50 out of 100, which is 50. What if there were 200 people who had used the internet and 130 of them said that they used it for general browsing? This figure of 130 can be expressed as a percentage of 200.

Presenting information : Have a go!

Try the following three percentage calculations:

  1. In a survey involving 700 people, 420 people said that they use the Internet for general browsing. What percentage is this?   
  2. In a group of 320 students, 120 said that they mainly use a laptop in their studies rather than a desktop computer. What percentage of students use a laptop?   
  3. On a production line for computer monitors, 3 out of 750 monitors are faulty. What percentage of monitors are faulty?

Check the answers!

  1. 420 / 700×100=60 So 60% of the people surveyed use the internet for general browsing. 
  2. 120 / 320×100=37.5 So 37.5% of the students use a laptop. 
  3. 3 / 750×100=0.4 So 0.4% of the monitors are faulty. 

How did you do?

To find out how to round up numbers go to Try this: Rounding

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