The teacher thinks of a four digit number made up of digits in the range 1 to 4. Each student guesses what the four digit number might be. The teacher gives one tick for each digit the student has in the right place. What number is the teacher thinking of?
Luis : 1434  Owen : 2334 
Landon : 3142  Diego : 1324 
Brian : 2234  Adam : 1121 
Adrian : 1344  Kyle : 1442 
Eric : 2432  Ian : 3322 
Nathaniel : 3334  Carlos : 4111 
Alex : 4412  Bryan : 2213 
Jagdish : 2342  Julian : 2324 
Sean : 4332  Carter : 4311 
Hayden : 4342  Jeremiah : 1332 
Note for Teacher: All of the students guesses above will probably not fit on the screen at the same time. You may wish to keep the lower guesses hidden so as not to make the activity too easy.
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Topics: Starter  Logic  Puzzles
Y5/6 working hard on the @Transum starter of the day. Fabulous maths reasoning and thinking skills. We love maths! pic.twitter.com/erhZztb4Nc
— Red Hill Field PS (@redhillfield) May 27, 2016
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2431
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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 a button above to regenerate another version of this starter from random numbers. There is a choice of three levels; easy, medium and hard.
Advanced: Finding a unique solution may not be possible. 

Possible strategy: Make a grid showing the possible digits which could appear in each of the four positions. By looking at the clues which do not have any ticks by them, cross of the digits which can't appear in each position.
There should now be only a limited choice for the correct digits:
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 a student version of this activity.
Transum.org/go/?to=frustration