Math CentralQuandaries & Queries


Question from Emma, a student:

Help me and my family cannot figure this out, it the last question on my paper. I need to know how to use place the brackets to make the following problem true.

39-4+6 divided by 3 to the power of 2 = 3

we have tried for three days and cannot get!


There is, as far as I know, no algorithm that solves all problems like this without some trial and error, so don't feel bad!

Now, a hint.

Try each operation in turn and try making it the last step; you then get an easier problem on each side. But with five numbers, one side has 1 or 2 of them so it's unambiguous - so you have only one simpler problem. [...] means parentheses are still undecided.

EG: 39 - [4+6/32] = 3 so [4+6/32] = 36
or (39-4) + [6/32] = 3 so [6/32] = -32
or [39-4+6] / (32) = 3, so ???
or ???

Good Hunting!



Try to make 39 - 36, using the fact that 36 is a square.


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