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Introducing the calculator

The calculator tool is a simple version of an ordinary pocket calculator.
It works in a very similar way, but we've removed the buttons you won't need.
You can use it with the calculations in the topics.
You can also use it to help with other calculations you have to do in everyday life.
Using the calculator tool is good practice for learning how to use a ‘real' calculator.

Getting to know the calculator

Before you use the calculator, you need to make sure you understand what all the buttons do.
Open the calculator tool on the toolbar near the top of screen and try it out for yourself.
When you click somewhere else on the screen the calculator will hide behind the topic window. If you can see it at the edge of the screen, click on it and it will come to the front again. If you cannot see it, you can open it again quickly by clicking the calculator tool icon at the top of the screen. You will not have lost the calculation you are working on.

Practising with the calculator

Working with money

When you type numbers into a calculator you need to be very careful you don't make mistakes.
When you are using the calculator to work out amounts of money, there are some extra things you need to think about.
You can't type in the £ sign. You just have to remember that your answer is in pounds — or pounds and pence.
Remember to type in the decimal point if there is one. £2.37 is very different to £237. The decimal point separates the pounds from the pence.
If you need to type in an amount in pence and one in pounds remember to put both in pounds. For example, 35p + £1.45 needs to be changed to £0.35 + £1.45. If you didn't then your answer would be £36.45 when it should be £1.80.
Remember, if your calculation is in pounds and the calculator shows an answer of 1.8 then this means £1.80.
If you want to type in £1 and 5p then remember to type it as £1.05. The 0 shows that there are no 10 pences. If you forgot the 0 then it would look like 1.5, which is £1.50.

Checking your answers

If you press the right buttons on a calculator in the right order you will get the right answer.
The problem is, it's quite easy to miss a step in your calculation or press the wrong button.
Don't just accept the answer a calculator gives you without question.
It's always a good idea to do a calculation twice. If you get a different answer the second time you need to check again more carefully.
Also try to do the calculation in your head very roughly. This can tell you whether you have made a mistake.