Random numbers

Pseudo random numbers and seeds
from random import *
randrange(1,11)   # random integer from 1 thru 10 inclusive 
random()          # random float between 0 and 1

Rounding idioms

2 * int(i)                       # will be even
if x % 2 != 0: x += 1            # will round an integer up to next even number
if x % 3 != 0: x += (3 - x % 3)  # will round an interger up to next multiple of 3