In mathematical terms, a factor is any of the numbers multiplied together to form the product of a multiplication problem. Weighting numbers allows you to give more importance to one number over another number. Weighted factors occur frequently in grade calculations performed by teachers. For example, if one assignment is worth 40 percent of the final grade and another worth 60 percent, calculating weighted factors ensures the accurate amount of a particular score counts toward the final grade.

Find the different factors and their respective weights. For example, assume a student has a 90 percent on a test worth 60 percent of his grade an 80 percent on a test worth 40 percent of his grade.

Multiply the factor by its respective weight. In the example, 90 percent times 60 percent equals 54 percent and 80 percent times 40 percent equals 32 percent.

Add the weighted factors together. In the example, 54 percent plus 32 percent equals 86 percent.