How to calculate the amount of paper grams~

How to calculate the amount of paper grams~

Such as 889 * 1194, 150 grams of coated paper, 6200 yuan / ton, calculate the amount of 1 ream of paper
Amount = 0.889 * 1.194 * 0.15 * 500 * 1 * 6.2 = 493.58 yuan