Using a Calculator (Cambridge (CIE) IGCSE Maths)

Using a Calculator

Why are calculator skills important?

• There are many special functions on a scientific calculator

  • To answer questions successfully you need to be able to use your calculator effectively

• You may need to use some of the functions on the calculator in other subjects such as Science

• There are many different models of calculator

  • Any scientific calculator will have the functions you need but may be accessed in different ways

  • You need to know how to use the features on your specific model

• If you have an old or very basic scientific calculator the functions may be used backwards

  • To find the sine of an angle on a newer calculator, type sin (57)

  • On an older calculator you may need to type 57 then press the sin button

• The notes below apply to most if not all scientific calculators but the images are based on the Casio fx-83GT

The Casio fx-83GTX Classwiz

How do I make sure that I have the correct settings on the calculator?

• Check you know how change the mode of your calculator

  • There is usually a button marked 'MODE'

  • Most calculators default to 'MATH' mode with the word MATH written across the top of the display or using a symbol

• The 'Angle Unit' needs to be degrees
  

  • There is usually a button marked 'SETUP' where you can find the angle unit options

  • A 'D' symbol at the top of the display is used to indicate that the calculator is in the degrees setting

• Make sure you can switch between 'exact' answers (e.g. fractions) and 'approximate' answers (e.g. decimals)

  • When in 'MATH' mode press the 'SD' button  to switch between answer types

What are the shortcut buttons on the calculator?

• There are several very useful shortcut buttons on the calculator that you should know

  • The fraction, square, cube, power and square root buttons are all frequently used

  • Use the 'SHIFT' (2^nd or INV) button to access functions including mixed numbers, cube roots, and n^th roots

Why is using brackets important?

• Applying brackets correctly on your calculator helps you to avoid errors in your calculations

  • Use brackets as you would in written mathematics

  • Put brackets around negative numbers in calculations

    • Remember,  gives you a different result to 

    • Use the '(-)' button for negative values, not the minus button

Which buttons are useful for trigonometry?

• Use the sin, cos and tan buttons when finding missing sides of a triangle 

  • Remember to make sure that your calculator is in degrees mode

• Use sin^-1, cos^-1 and tan^-1 when finding missing angles of a triangle

  • Access these by using the 'SHIFT' button

• When using a trig function, the calculator gives you an open bracket '('

  • Remember to use a closed bracket ')' after typing the angle in

Which buttons are useful for standard form and calculations involving π?

• To write a number in standard form on the calculator, use the ×10^x 

  • Modern calculators display standard form in the way it is written, e.g., 2 x 10⁵

  • Older models may use a small capital letter 'E' in place of ×10^x, e.g., 2E5 

•   is often near the standard form button

  • You may need to use the 'SHIFT' button to access it

What is the Ans function?

• The Ans (answer) button recalls the last answer the calculator calculated

  • Use this when working with decimals in the middle of solutions to avoid rounding until your final answer

What is the table function?

• If your calculator has a table function or mode it can be used in 'complete the table of values and draw the graph' type questions

  • This can help you to reduce the number of calculations you have to do

  • It can also help to reduce errors

How do I use my calculator for time calculations?

• Remember that time can be given in different formats

  • Time can be given in hours/minutes/seconds, e.g. 3 hours 46 minutes

  • Time can be given as a decimal, e.g. 2.7 hours

• You can use the degrees, minutes and seconds function  to enter time on your calculator

  • E.g. 3 minutes 45 seconds would be entered as

  • You can convert between an answer on the calculator, given in either format of time, by pressing this button