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?
Aaron : 3133  Lucas : 2424 
Luis : 4142  Owen : 1423 
Landon : 1323  Diego : 4213 
Brian : 1114  Adam : 4241 
Adrian : 2222  Kyle : 2311 
Eric : 2131  Ian : 2334 
Nathaniel : 1112  Carlos : 3221 
Alex : 3433  Bryan : 2333 
Jagdish : 4213  Julian : 3221 
Sean : 2114  Carter : 3332 
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.
Topics: Starter  Logic  Puzzles
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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:
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