The figure provided represents the domestic market for calculators. A graph plots a demand and supply curve with Quantity of calculators along the horizontal axis and Price of calculators along the vertical axis. The demand curve starts at 45 dollars for 0 calculators and has a negative slope that ends at 10 dollars for 700 calculators. The supply curve starts at the origin and has a steep positive slope that ends at 45 dollars for 500 calculators. The curves intersect at 300 calculators, 30 dollars. After trade, at a world price of $10, the producer surplus, in numerals, is $_____