Jack thinks of a number.
He multiplies this number by 5 then subtracts 8.
His answer is 37. What was Jack's original number?
Jack's friend thinks of a number.
He then does the following operations:
Multiply by 2, subtract 5, multiply by 2 then add 30 (in that order). He finds that the number he ends up with is 9 times his original number.
What was Jack's friend's original number?
Change NumbersEasier Questions
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Too difficult? There are some simpler questions like this on the THOAN Starter page.
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Have you read Craig's book yet?Craig Barton must surely be the voice of Mathematics teachers in the UK. His wonderful podcasts interviewing the industry experts have culminated in this wonderful book. As Craig says: "I genuinely believe I have never taught mathematics better, and my students have never learned more. I just wish I had known all of this twelve years ago..." more... "How I wish I’d taught maths' is an extraordinary and important book. Part guide to research, part memoir, part survival handbook, it’s a wonderfully accessible guide to the latest research on teaching mathematics, presented in a disarmingly honest and readable way. I know of no other book that presents as much usable research evidence on the dos and don’ts of mathematics teaching in such a clear and practical way. No matter how long you have been doing it, if you teach mathematics—from primary school to university—this book is for you." Dylan Wiliam, Emeritus Professor of Educational Assessment, UCL. 
Casio Classwiz CalculatorThere is currently a lot of talk about this new calculator being the best in its price range for use in the Maths classroom. The new ClassWiz features a highresolution display making it easier to view numerical formulas and symbols but it isn't a graphical calculator as such (it has the capacity to draw graphs on your smart phone or tablet, via a scannable QR code and an app). As well as basic spreadsheet mode and an equation solving feature you also get the ability to solve quadratic, cubic or quartic polynomial inequalities and the answer is given just as it should be written down, using the correct inequality symbols! This calculator has a highperformance processor and twice the memory of previous models ensuring speedy operation and superior computational power.more... 
GCSE Revision and PracticeWhatever exam board you use for GCSE Mathematics, this book by David Rayner remains an allround winner. With this latest edition presented in full colour and completely updated for the new GCSE(91) specifications, this uniquely effective text continues to increase your chance of obtaining a good grade. This book is targeted at the Higher tier GCSE, and provides a wealth of practice with careful progression, alongside substantial revision support for the newstyle grading and exam questions. With all the new topics included, and a dedicated section on using and applying mathematics, this unique resource can be used either as a course book over two or three years or as a revision text in the runup to exams. more... 
Teacher, do your students have
access to computers? 

Here a concise URL for a version of this page without the comments.
Here is the URL which will take them to the Think Of A Number exercise.
Here is the URL which will you to our eQuation Generator which provides unlimited practice solving linear equations.