"Um, sorry for not being explicit - if I say for people to raise they're hand when they're done, that's so I know everyone is done, and meanwhile, everybody gets a chance to try on their own before hearing anybody else's result."

"At least you didn't say how you did the calculation, so others can, perhaps, do their own calculations and see if they think yours is correct."

Keltham comes over to look at Alexandre's scratch paper, if any; what calculation does Alexandre seem to have done?

"Um, sorry for not being explicit - if I say for people to raise they're hand when they're done, that's so I know everyone is done, and meanwhile, everybody gets a chance to try on their own before hearing anybody else's result."

"At least you didn't say how you did the calculation, so others can, perhaps, do their own calculations and see if they think yours is correct."

Keltham comes over to look at the scratch paper, if any; what calculation seems to have been done?