Mental Arithmetic: Practice Set 3
Mental Arithmetic: Practice Set 3 is a third timed set of 13+ Common Entrance mental arithmetic questions, continuing the rapid, no-written-working practice from Sets 1 and 2 across the four operations, fractions, percentages, ratio, rounding and simple algebra.
Before you start
Make sure you're comfortable with these topics first:
Method
- Round each number in a calculation to 1 significant figure first to form a quick estimate, then use this to check your final mental answer is a sensible size.
- Practise adding and subtracting negative numbers by picturing a number line, remembering that subtracting a negative is the same as adding a positive.
- Learn quick percentage building blocks (10%, 5% and 1%) so any percentage can be built up or down from them in a couple of steps.
- Break a two-digit multiplication into tens and units, for example 23 x 6 = (20 x 6) + (3 x 6), and add the two parts together.
- For a multi-part question, answer each part in order and keep the units the same throughout, converting once rather than repeatedly.
- Say your working through in short steps, so you keep track of where you are in a multi-step calculation.
Worked example
Work out -8 + 5 - (-6).
- Rewrite subtracting a negative as adding: -8 + 5 - (-6) becomes -8 + 5 + 6.
- Add the first two terms: -8 + 5 = -3.
- Add the remaining term: -3 + 6 = 3.
- So the answer is 3.
Practice questions
Type your answer and press Check to be marked straight away, or reveal the answer and mark yourself.
Q1Work out 12 x 7.Show answer
Answer: 84
Q2Find 30% of 150.Show answer
Answer: 45 (10% = 15, so 30% = 45)
Q3Round 6.849 to 1 decimal place.Show answer
Answer: 6.8
Q4Work out -4 - 7.Show answer
Answer: -11
Q5Simplify 6a + 9 - 2a - 4.Show answer
Answer: 4a + 5
Q6A pack of 24 pencils costs 3.60 pounds. Work out the cost of one pencil.Show answer
Answer: 15p (3.60 / 24 = 0.15)
Exam-style questions
Written in the style of a 13+ Common Entrance exam paper, with a full mark scheme.
Work out 3 x (7 - 2)^2.
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Tick each line you got. Your score builds from the marks on the scheme.
Nothing ticked yet - 2 available
Freya has 3.50 pounds. She buys 2 notebooks at 85p each and a pen for 45p. Work out how much money she has left.
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Tick each line you got. Your score builds from the marks on the scheme.
Nothing ticked yet - 3 available
A number is increased by 20% to give 96. Work out the original number.
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Tick each line you got. Your score builds from the marks on the scheme.
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Free printable worksheet
Want more practice on paper? Download the mental arithmetic: practice set 3 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 3 of 13+ Maths Workbook, the whole course as one free printable PDF.
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