There are 10 variables for calculating particle size. Each variable is represented by two numbers. The first number is either 1 for percent on or 2 for percent through. The second number (1 through 5) indicates which sieve is being calculated. For example (2 3) means percent through the third sieve. Numbering sieves (1 through 5) from top to bottom the percent on and percent through each sieve can be calculated using the appropriate calculations as follows: