Alejandro thinks of a number.
He then does the following operations:
Multiply by 3, subtract 3, multiply by 3 then add 57 (in that order).
He finds that the number he ends up with is 15 times his original number.
What was Alejandro's original number?
Change NumbersEasier Questions
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Too difficult? There are some simpler questions like this on the THOAN Starter page.
Note to teacher: Doing this activity once with a class helps students develop strategies. It is only when they do this activity a second time that they will have the opportunity to practise those strategies. That is when the learning is consolidated. Click the button above to regenerate another version of this starter from random numbers.
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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.