I received a message asking me why I use so often numbers like 1e6 (exponential form) instead of writing down the whole numbers. I never thought on this before. However, I can assure that it’s not because I’m lazy and don’t like typing long numbers. In fact, thinking on this made me find a reasonable explanation for this: With very large or very small numbers one can end up miscounting some zeros, hence we sometimes can avoid this by typing those numbers in exponential format. So 1e6 is 110^6=1,000,000 and 2.1e-4 is 5.110^-4=0.00051. In Stata one can figure out what the exponential number means by typing: display 1e6, whereas in R it is enough to type: format(1e6, scientific=F). Now, if you want R to display only scientific number instead, you want to set options as: options(scipen = -10).