Timed Arithmetic Challenge
The Timed Arithmetic Challenge is a strictly timed set of calculations using all four operations, with whole numbers and decimals, designed to mirror the mental arithmetic and calculation sections of GL and CEM 11+ papers. The challenge is not the difficulty of any single calculation but sustaining speed and accuracy across many questions in a row, without a calculator.
Before you start
Make sure you're comfortable with these topics first:
Method
- Build automatic recall of number bonds and times tables through regular practice, so calculations do not have to be worked out from first principles under time pressure.
- Use efficient written methods, such as column addition or short multiplication, for any calculation too large to do purely in your head.
- Work through the questions in order but skip and return to any calculation that is taking noticeably longer than the others.
- Write brief working for multi-step calculations, so a single slip only costs part of the working rather than the whole answer.
- Save the final part of the time to go back and check the calculations you were least confident in, rather than re-checking everything equally.
- If unsure where a decimal point belongs, use a quick estimate (rounding the numbers) to sanity check the size of your answer.
Worked example
Under timed conditions you must work out 7.2 x 0.4 within 20 seconds, without a calculator.
- Ignore the decimal points for now and multiply the digits as whole numbers: 72 x 4 = 288.
- Count the total number of decimal places in the original numbers: 7.2 has 1 decimal place and 0.4 has 1 decimal place, giving 2 in total.
- Place the decimal point in 288 so there are 2 digits after it: 2.88.
- Final answer: 2.88.
Practice questions
Type your answer and press Check to be marked straight away, or reveal the answer and mark yourself.
Q1Work out 34 + 89.Show answer
Answer: 123
Q2Work out 205 - 78.Show answer
Answer: 127
Q3Work out 6 x 34.Show answer
Answer: 204
Q4Work out 168 / 7.Show answer
Answer: 24
Q5Work out 4.5 + 3.75.Show answer
Answer: 8.25
Q6Work out 9.6 - 2.35.Show answer
Answer: 7.25
Q7Work out 12 x 0.5.Show answer
Answer: 6
Exam-style questions
Written in the style of a 11+ exam paper, with a full mark scheme.
You have 60 seconds to complete four calculations. Work out each one, showing brief working where helpful: (a) 47 + 168, (b) 304 - 86, (c) 15 x 12, (d) 245 / 5.
Show mark scheme
Tick each line you got. Your score builds from the marks on the scheme.
Nothing ticked yet - 4 available
Work out 8.4 x 0.5 and then add 3.6 to your answer, showing each step. Give a reason why estimating first (for example, rounding to 8 x 0.5 = 4) helps you check whether 8.4 x 0.5 is likely to be correct.
Show mark scheme
Tick each line you got. Your score builds from the marks on the scheme.
Nothing ticked yet - 4 available
Free printable worksheet
Want more practice on paper? Download the timed arithmetic challenge worksheet pack - 17 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 16 of 11+ Maths Workbook 1, the whole course as one free printable PDF.
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