If you are refering to paint mixing sticks the general rule is that the first set of numbers is for the paint or primer that you are using. The second set is for any hardener that the product uses,and the third set is for any thinners or reducers the product uses. To use first pour your paint up to a number, lets use 2 for an example. Next pour your hardener up to the 2 in the second column of numbers. Then pour your reducer up to the 2 in the third column. Each product that you are using usually uses a specific stick so make sure you have the correcy one for what you are using.