What are the rulings for Zakat on trade goods for bookstores in the following matters: Is the rent of the premises deducted from the capital before calculating the Nisab? What is the gold standard (purity) considered for calculating the Nisab of 85 grams? Is the photocopier included in the capital subject to Zakat? Is it permissible to give Zakat to a poor family monthly, or must it be given all at once after a full year (Hawl)?

1. The shop's rent is deducted from the Zakat money.

2. The nisab for banknotes is determined by the equivalent of 85 grams of gold or 595 grams of silver, with 24-karat gold being used for the gold calculation.

3. The photocopier and fixed assets that are not for sale are not assessed when calculating the shop's Zakat.

4. Paying Zakat in installments is permissible before it becomes due (after reaching the nisab and before the completion of the hawl), but it is not permissible to pay it in installments after it becomes due, because the principle is to pay it immediately.