Puzzle Details

What value of * makes the following correct:

Checking that 3 works:

3     3     3     3
-  -  -  +  -  =  -
3     2     4     12

1 - 1.5 + 0.75 = 0.25

0.25 = 0.25, which confirms that 3 is correct.

To deduce the answer directly from the question, we can multiply throughout by 12,

*     *     *     *
-  -  -  +  -  =  -
*     2     4     12

to give:

12 - 6* + 3* = 1*

12 - 3* = 1*

12 = 4*

3 = *

As required.

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