How is it done????? I'm sure someone on here knows. thats partly the answer....all the answers are multiples of nine so if you think of number between 10-19...no matter what number you choose the answer will be 9..........if you choose a number between 20-29 the answer will be 18.....between 30-39...the answer 27 and so on and so forth. The symbols change every go.. just to confuse you plus they give some other numbers the same symbol as well just to try and show that there isnt a pattern.

Spookily though, it doesn't seem to work when you just pick a random number without doing the adding/subtracting bit first.... :shock: BMB xx

Didn't understand DazzyBoys explanation at all, but EvilDaddyBadger has explained it all to me using the power of algebra and I am now much wiser and more powerful. And slightly embarrassed... BMB xx