0.333 kg. There are many kinds of algorithms are very simple, only one algorithm is provided here: each cup of coffee needs 6 grams of coffee powder and 4 grams of sugar cubes, that is, each consumption of 6 grams of coffee powder needs 4 grams of sugar cubes, the ratio is: 2\/3, and then multiplied by the total weight of coffee powder, the number of sugar cubes required to finish the coffee powder: 0.333KG.