A cup is a measurement of volume, not mass. The conversion should be made into milliliters.
There are 4 fluid ounces in a cup.
1 ounce [US, liquid] = 29.57353 milliliters
Therefore, 4 ounces = around 120 ml
Now, read the scoop size on the container and figure out how many milliliters are in a scoop or serving. Found out how many servings are in the container. Multiply the mass of the serving size by the number of servings to get the total mass in grams of the mix. Multiply the volume of a scoop (milliliters) by the serving size to get the total volume of mix.
Now, create a ratio of mass to ml by dividing the mass in grams by the volume in millileters.
Multiply this by the volume of a cup (120 ml) to find out how many grams of mix a cup has.
Now, create another ratio of carbs to serving size mass by dividing carb grams by total grams.
96 grams carbs/106 grams = .89, or 90% carbs per serving by mass.
Take the grams in a cup and multiply by .89 to find out how many grams of those are carbs.
Peace