New
New
Lesson 1 of 1
  • Year 10
  • Foundation

Accuracy of final answers

I can appreciate the accuracy in leaving an answer without carrying out the final operation.

Lesson 1 of 1
New
New
  • Year 10
  • Foundation

Accuracy of final answers

I can appreciate the accuracy in leaving an answer without carrying out the final operation.

Lesson details

Key learning points

  1. There is always a choice regarding how you represent a value.
  2. You need to consider the most suitable way for the situation.
  3. Rounding reduces accuracy so a rounded answer is not always useful.
  4. There are agreed forms: one operation remaining and the result of the operation would produce a non-terminating decimal.
  5. Surd form is one such acceptable way.

Keywords

  • Recurring decimal - A recurring decimal is one that has a digit or sequence of digits that repeat endlessly.

  • Terminating decimal - A terminating decimal is one that has a finite number of digits after the decimal point.

  • Rational number - A rational number is one that can be written in the form a/b where a and b are integers and b is not equal to 0.

  • Irrational number - An irrational number is one that cannot be written in the form a/b where a and b are integers and b is not equal to 0.

  • Surd - A surd is an irrational number expressed as the root of a rational number.

Common misconception

Surds are any number with a root symbol.

√4 is not a surd as it is equivalent to 2.


To help you plan your year 10 maths lesson on: Accuracy of final answers, download all teaching resources for free and adapt to suit your pupils' needs...

Pupils may struggle with 0 not being a natural number. Natural numbers are positive whole numbers. 0 is neither positive nor negative and therefore cannot be a natural number.
Teacher tip

Equipment

Licence

This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Prior knowledge starter quiz

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6 Questions

Q1.
Which of these numbers is not a whole number?

12
16
7
Correct answer: 2.3

Q2.
Press the $$\pi$$ button on your calculator. What is the sixth digit?

Correct answer: 9
6
5
2

Q3.
Enter $$\sqrt{5}$$ on your calculator. What is the second digit?

Correct Answer: 2, two

Q4.
A circle has a diameter of 3 cm. What is the circumference of the circle to 1 decimal place?

Correct Answer: 9.4, 9.4 cm

Q5.
Enter $$\sqrt[3]{64}$$ on your calculator. What is the answer?

Correct Answer: 4, four

Q6.
Which of these is an example of a recurring decimal?

1.2
1.252525253
Correct answer: $$1.\dot{6}$$
2.222

Assessment exit quiz

Download quiz pdf

6 Questions

Q1.
True or false? The group of integers includes negative numbers.

Correct answer: True
False

Q2.
A number is one that can be written in the form $$a \over b$$ where $$a$$ and $$b$$ are both integers and $$b \ne 0$$.

Correct Answer: rational

Q3.
Identify the rational number.

$$\pi$$
Correct answer: 0.263
$$\sqrt 3$$
$$\sqrt 2$$

Q4.
Which of these is a surd?

Correct answer: $$\sqrt {21}$$
$$\sqrt {25}$$
$$\sqrt {36}$$
$$\sqrt {49}$$

Q5.
Which of these is a surd?

$$\sqrt[3] {64}$$
$$\sqrt[3] {27}$$
Correct answer: $$\sqrt[3] {16}$$
$$\sqrt[3] 8$$

Q6.
Which of these is a surd?

$$\sqrt {1 \over 25}$$
$$\sqrt {0.25}$$
Correct answer: $$\sqrt {1 \over 6}$$
$$\sqrt {1 \over 49}$$