There are many other quick techniques they teach you in Math. This one is just interesting I guess. Competition is really strong there.

 

I still prefer the calculator

 

I prefer my brain.

 

I prefer my toes.

 

 

How? Because they don't use condoms? Same with the Indians - their population rises 12M per month! To give you an idea, it only takes about a year to add a Japan-size or half the US population to their country.

Edit: It's 1.2M per month, not 12.