elron

I was reading Elli's thread with her tricks , so here's mine , no tricks - just plain math .


1,5,6,7 . with these figures using only the four basic arithmetics : +,-,*,/ get me 21 .

You may not use any number more than once (or else use the number '1' 21 times .... duh) .

Just know that we brought this up to a math proffesor back then at university times , and he gave up after 3 hours

If anyone knows - dont spoil it , icq me the answer instead 63274674


Good Luck