13 September 2015

Math puzzle (relatively easy)

Yet another custom when my nephews and niece are around in their granddad’s house along with me is to go out for a walk after dinner and solve mathematical or logic puzzles. You might remember how, last time, we got stuck on getting two numbers (was it 19 and 21??) using the digits 1, 2 and 3 and any number of operators.

Last night, we came up with a variation – Using the digits 1, 2 and 4 and no other digits (and you can use them only once) you have to come up with 1 thru 25. 20 posed an interesting problem. Can you try it?

Using 1, 2 and 4 get 20. You can use any number of mathematical operators and symbols any number of times (but no other digits than the above and that too only once). For the record, trigonometric functions are not allowed since there is an assumption of the unit (radians/degrees). We reluctantly accept logarithms but try to find alternate answers. We certainly accept concatenation. Meaning you can get 16 by simly saying 12+4.

Posted September 13, 2015 by Rajib Roy in category "Puzzles", "Vacations


  1. By Rajib Roy on

    You must use 4.
    And that is a correct answer Sanjib and Ranajoy. I came at it as (4/2)/.1 There is another approach that worked. Want to try some more?


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