Math Is Fun Forum

rangela

Guest

Help!!!!

hi can anyone help my 8yr old has given me his home work and im stuck...
the question is: use each of the numbers 1 to 8.write one number in every circle so that each line of three numbers adds up to 12.     

     o
     ooo
   ooo
       o

any help would be greatful
thanks angela

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Help!!!!

The central four numbers are part of 2 lines, and the outer four are only part of one.
The numbers from 1 to 8 total 36, and the four lines need to total 4x12 = 48.

From this, you can work out that the central four numbers also have to total 12.

Try filling in the centre so that it keeps to this fact. Once you have the centre, the outer four numbers are already determined. If none of the numbers clash then you've done it!
If some do, then try a different centre. I think there are only about 4 different centres to try (counting reflections and rotations as the same).

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Why did the vector cross the road?
It wanted to be normal.