There are 3 factor pairs of 18:
18 = 1 x 18
18 = 2 x 9
18 = 3 x 6
3.785 litres in a US gallon
'Party Dots' is a series of red dots starting at the top of your arm and extending down to the nail of the middle finger. This line can be crooked or straight, depending on how drunk you are when you get them.
Any calculated number from a sample from the population is called a 'statistic', such as the mean or the variance.
You'll want to look up variance and standard deviation.