Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ ¹ ² ³ °
 

You are not logged in. #1 20110220 03:10:23
Multiply 11 up to 19 (shortcut)I was astounded an hour ago when igloo myrtilles fourmis #2 20110920 08:07:04
Re: Multiply 11 up to 19 (shortcut)When I do mental calculations, I normally look for shortcuts, and different calculations often require different shortcuts. For 16 × 19: And for 12 × 16: #3 20110921 22:32:38
Re: Multiply 11 up to 19 (shortcut)Hi Sylvia104;
Nice signature but I already knew. In mathematics, you don't understand things. You just get used to them. I have the result, but I do not yet know how to get it. All physicists, and a good many quite respectable mathematicians are contemptuous about proof. #4 20120211 19:02:01
Re: Multiply 11 up to 19 (shortcut)hi xhintim
that's exactly how bobbym's signature goes! The limit operator is just an excuse for doing something you know you can't. “It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman “Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment 