13+ Common Entrance · Topic guide

Mental Arithmetic: Practice Set 2

Mental Arithmetic: Practice Set 2 is a second timed set of 13+ Common Entrance mental arithmetic questions, giving further rapid practice at the four operations, fractions, percentages, ratio and simple algebra without long written working, alongside the questions in Mental Arithmetic (CE.M7).

Year 7-8 (13+)MathsISEB

Before you start

Make sure you're comfortable with these topics first:

Method

  1. Revise your times tables to 12 x 12 and their matching division facts, since Set 2 keeps testing instant recall rather than working out.
  2. Use doubling and halving to simplify awkward multiplications and divisions, such as multiplying by 4 by doubling twice, or dividing by 5 by dividing by 10 then doubling.
  3. Convert between common fractions, decimals and percentages instantly (1/2, 1/4, 1/5, 1/10 and their percentage and decimal forms), since Set 2 often swaps between the three within one question.
  4. For multi-step word problems, work out and note the answer to each step in order, rather than trying to hold every number in your head at once.
  5. For ratio and proportion questions, find the value of one part first, then scale up or down to answer what is actually being asked.
  6. Sense-check every answer against the size of the numbers in the question before moving on, since an unrealistic answer often means a step was mixed up.

Worked example

A recipe for 8 people uses 600g of flour. Work out how much flour is needed for 6 people.

  1. Find how much flour is needed per person: 600 / 8 = 75g.
  2. Multiply by the number of people needed: 75 x 6 = 450.
  3. So 450g of flour is needed for 6 people.

Practice questions

Type your answer and press Check to be marked straight away, or reveal the answer and mark yourself.

Q1Work out 15% of 60.Show answer

Answer: 9 (10% = 6, 5% = 3, 15% = 9)

Got it right?
Q2Find 3/4 of 88.Show answer

Answer: 66 (88 / 4 = 22, then 22 x 3 = 66)

Got it right?
Q3Work out 7 x 9 - 4 x 5.Show answer

Answer: 43 (multiply first: 63 - 20 = 43)

Got it right?
Q4A journey of 240 km takes 4 hours at a constant speed. Work out the speed in km/h.Show answer

Answer: 60 km/h (240 / 4 = 60)

Got it right?
Q5Simplify the ratio 18:24 to its simplest form.Show answer

Answer: 3:4 (divide both parts by 6)

Got it right?
Q6Work out -9 + 15.Show answer

Answer: 6

Got it right?

Exam-style questions

Written in the style of a 13+ Common Entrance exam paper, with a full mark scheme.

Q1[2 marks]

Work out 6^2 - 5^2.

Show mark scheme

Tick each line you got. Your score builds from the marks on the scheme.

Nothing ticked yet - 2 available

Got it right?
Q2[3 marks]

A shop buys pens for 40p each and sells them for 65p each. Work out the profit made on selling 30 pens.

Show mark scheme

Tick each line you got. Your score builds from the marks on the scheme.

Nothing ticked yet - 3 available

Got it right?
Q3[4 marks]

Layla shares 84 sweets with her brother in the ratio 5:2. She then gives 1/3 of her share to a friend. Work out how many sweets Layla has left.

Show mark scheme

Tick each line you got. Your score builds from the marks on the scheme.

Nothing ticked yet - 4 available

Got it right?

Free printable worksheet

Want more practice on paper? Download the mental arithmetic: practice set 2 worksheet pack - 13 pages of exam-style questions with a full mark scheme. One email opens every download in this browser for 14 days - no account, no card. Print it for personal and classroom use.

This topic is chapter 2 of 13+ Maths Workbook, the whole course as one free printable PDF.

Next topics

Ready to practise mental arithmetic: practice set 2? Add it to a printable topic pack for this student in the Pack Builder.

Add to my pack

Not quite what you needed?

Tell us what is missing on mental arithmetic: practice set 2, or which topic to write up next. Every request is read, and we reply to every one.

Build a full practice pack.

This topic is one of hundreds in the library - pick the ones a student needs and generate a printable PDF in minutes.