What is a square root of a number?

A square root of a number is a value that, when squared , gives the original number . E.g. 3 is the square root of 9 because 3 2 = 3 x 3 = 9.

True or False? Cube roots of negative numbers do not exist .

False. The cube root of a negative number will also be a negative number . For example, -5 is a cube root of -125.

GCSEMathsEdexcelFoundationFlashcardsNumberPowers, Roots & Standard Form

Powers, Roots & Standard Form (Edexcel GCSE Maths: Foundation): Flashcards

Exam code: 1MA1

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What is a square root of a number?

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Cards in this collection (9)

What is a square root of a number?
A square root of a number is a value that, when squared, gives the original number.
E.g. 3 is the square root of 9 because 3² = 3 x 3 = 9.
True or False?
Every positive number has two square roots.
True.
Every positive number has two square roots, one positive and one negative.
E.g. $\sqrt{64} = 8$ and $- 8$
True or False?
Cube roots of negative numbers do not exist.
False.
The cube root of a negative number will also be a negative number.
For example, -5 is a cube root of -125.
Define the term reciprocal.
The reciprocal of a number is the number that you multiply it by to get 1.
For example, $\frac{2}{3}$ is the reciprocal of $\frac{3}{2}$ .
How do I estimate a root, e.g. the square root of 27?
You can estimate the root of a number by finding the closest integer roots either side of it.
E.g. To find $\sqrt{27}$
$\sqrt{25} = 5$ and $\sqrt{36} = 6$
So $\sqrt{27}$ is between $5$ and $6$
What does a number written in standard form look like?
A number in standard form looks like $a \times 10^{n}$ , e.g. $5.2 \times 10^{3}$ .
It is a number between 1 and 10 multiplied by a power of ten.
When a number is written in standard form $a \times 10^{n}$ , which values can $a$ be?
For $a \times 10^{n}$ , $a$ is at least 1 and less than 10, $1 \leq a < 10$ .
This means there is one non-zero digit before the decimal point.
True or False?
When a number is written in standard form $a \times 10^{n}$ , $n$ can be a fraction.
False.
For a number written in standard form, $a \times 10^{n}$ , the value $n$ must be an integer.
It can be zero, positive or negative.
When a value between 0 and 1, is written in standard form $a \times 10^{n}$ , what type of number will $n$ be?
If a value is between 0 and 1 then when it is written in standard form, $n$ will be a negative integer.
E.g. 0.083 would be written as 8.3 x 10^-2.

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