First of all, you have to open and close positions. If the opening price is1kg = 4,000 yuan, which is the current silver price, and the handling fee is 0.5 ‰ of the unilateral transaction amount, then the handling fee required for opening the position now is100 * 4,000 * 0.0005 = 200 yuan, and the silver price you need for closing the position is1kg = 4,500 yuan. Then the handling fee for your liquidation is 100*4500*0.0005=225 yuan, then the handling fee for your first-hand transaction, that is, buying and selling, is 425 yuan, and the spread is 5, so you need 5* 100=500 yuan, so your first-hand 100kg needs 425 yuan.