In many situations, we need to calculate a weighting of the values from several columns, either to generate the final course grade or for partial grades. 

The first thing we must keep in mind when creating calculations is that if we are going to weight, all columns must be on the same scale. We cannot average three elements graded, for example, out of 10, 20, and 32. We must first convert them all to the same scale, for example 10, and then perform the calculations.

Setting the column to percentage only shows us the value as a %, but we must remember that Blackboard always, always performs calculations with points and then shows us the result in the format we requested (percentage, scale, etc.).

Knowing this, performing a weighting is simple.

• Create all columns with the same scale (for example, out of 10 points) or convert all grades to a base of 10
• Create the calculated column, select Weighting, and add the percentage weighting for each of the displayed categories. 
• Any categories that will not participate in the calculation can be excluded by clicking the prohibited symbol.
• To fix a percentage, lock it by closing the padlock. 
• Percentages refer to the category, with everything inside the category weighted in two different ways: either all activities in the category weigh equally, or they weigh according to the number of points they contribute.
• If you need only one element from a category to be included in the weighting, you can unlink it from the category by clicking the link icon.
• The percentages must add up to 100.