Food manufacturers often round the amount of calories in a food serving up or down. in this nutrition facts panel, the manufacturer says there are 170 kcal per serving. if that same food label says there are 1.5 grams of total fat, 36 grams of total carbohydrate, and 4 grams of protein, how many calories are really in one serving?

Answer;
173.5  kilocalories.

Explanation;
1 gram of fat contains 9 kilo calories
1 gram of carbohydrates contain 4 kilo calories 
1 gram of protein contains  4 kilo calories
Thus;
1.5 grams of fat will have; 9 × 1.5 = 13.5 kilo calories
36 grams of carbohydrates; 36 × 4 = 144 kilo calories
4 grams of proteins;              4 × 4   = 16 kilo calories

This gives a total of 173.5 kilo calories