Unit 2 Section 3 : Index Notation
In the previous section on prime factors, you will have seen occasional use of index notation.
For example, the number 360 can be written as either 2 × 2 × 2 × 3 × 3 × 5 or as 2^{3} × 3^{2} × 5.
2^{3} is pronounced "2 to the power of 3" or "2 cubed", and means 2 × 2 × 2.
3^{2} is pronounced "3 to the power of 2" or "3 squared", and means 3 × 3.
In general, a^{n} is pronounced "a to the power of n" and means "n lots of a, multiplied together".
Numbers written in index notation are often called powers.
Strictly speaking, a is the base number, and n is the power.
Using a calculator
A calculator can be used to work out one number to the power of another.
The index button is usually marked x^{y} or y^{x}.
Sometimes you need to press SHIFT or 2ndF to use this button
For example, to calculate 5^{4}, you may need to press
You should find out which buttons you need to use on your calculator.
Make sure that you get the correct answer of 625 for the calculation above.

Practice Questions
Work out the answers to the questions below then click on the button marked
to see whether you are correct.
Practice Question 1
(a) Calculate 2^{4}
(b) Calculate 7^{3}
(c) Calculate 10^{5}
Practice Question 2
(a) What is the missing number in the statement below?
(b) What is the missing number in the statement below?
Exercises
Work out the answers to the questions below and fill in the boxes. Click on the
button to find out whether you have answered correctly. If you are right
then will appear and you should move on to the next
question. If appears then your answer is wrong. Click
on to clear your original answer and have another go.
If you can't work out the right answer then click on
to see
the answer.
You have now completed Unit 2 Section 3
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Produced by A.J. Reynolds February 2003