Exercise 1.5 Primes, Powers And Square Roots Worksheet - Heinemann Maths Zone Page 2
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1
2
3
4
5
6
7
8
9
10
112
For 4
we say ‘four squared’ or ‘four to the power of two’ or ‘four to the
Power Man to base …
second power’.
can you hear me?
3
For 5
we say ‘five cubed’ or ‘five to the power of three’ or ‘five to the
third power’.
4
For 7
we say ‘seven to the power of four’ or just ‘seven to the fourth’.
Another word for index is exponent. Numbers written using index
notation are in index form or exponential form.
3
4
is in index form.
4 × 4 × 4 is in expanded form.
worked example 11
3
(a) Write out 4
in expanded form and work out the answer.
4
(b) Write out 7
in expanded form and work out the answer.
Steps
Solutions
3
= 4 × 4 × 4
(a) 1. Write 4
in expanded form.
3
(a) 4
= 64
2. Write down the answer.
4
= 7 × 7 × 7 × 7
(b) 1. Write 7
in expanded form.
4
(b) 7
= 2401
2. Write down the answer.
e
eTutorial
Powers on calculators
Many calculators have a key to help you work quickly with powers, usually
y
x
3
or
. For example, if you want to work out 12
, press
1
2
^
=
x
y
x
2
2
3
. To work out 5
, simply press
5
.
Squares and square roots
A number is called a perfect square if it can be found by multiplying another
number by itself (i.e. by squaring the other number).
Finding the square root is the opposite to squaring a number. For example,
to find the square root of 16, you have to think of a number that when
multiplied by itself gives you 16. The number is 4 since 4 × 4 = 16.
= 4.
This means the square root of 16 is 4. We write this as
16
You can use your calculator to help with some calculations. Your calculator
will have a key like this:
.
e
=
eTutorial
To find
2304
, press
2
3
0
4
e
eTutorial
or
2
3
0
4
depending on the type of calculator.
e
eTutorial
Then read off the answer: 48.
18
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M A T H S Z O N E
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