If you are out of ideas for how to push your kid into learning maths, maybe this Magic Chrystal Ball game will help. It is simple and effective, while being fun. Requires Macromedia Flash though.
If you are out of ideas for how to push your kid into learning maths, maybe this Magic Chrystal Ball game will help. It is simple and effective, while being fun. Requires Macromedia Flash though.
It took me some time to figure this one out. :)
As leonid correctly guessed and I expanded his guess,
(A*10+B)-(A+B) = 10A+B-A-B = 9A
which always gives out numbers divisible by 9.
How about games with integrals and derivatives next time?
[2] Yeah, well… the formula was easy. But the real nice touch to the whole thing was how they reloaded the table with symbols and how they used a random symbol for 0.