I need to figure out what the answer is show i can check my answer no examples in text book. How do i start working out the National Income.?

Government spending R 18 000
Depreciation R 6000
Investment Spending R 35 000
Net Foreign Spending R 12 000
Indirect Taxes R 14 500
Net factors Payment(R 4000)
Consumer Spending R 30 000
Subsidies R 4000

GDP at factors cost=Remuneration +Net trade surplus +Depreciation
4000 + 12000 + 6000 = 22000
GDP at market prices=GDP at factors cost + Indirect taxes – Subsidies
22000 + 14500 – 4000 = 32500
GNP= GDP at market prices – Net factors payment
32000 – 4000 = 28500
National income = Net national product = GNP – Depreciation
28500 – 6000 = 22500

Isn't depreciation supposed to be a debit (negative) value?

Start with your revenues, then subtract your expenses to get income.