The consumer surplus is equal to the difference between marginal benefit and price. It is added up for all the units the consumers buy. The producer surplus is equal to the difference between price and cost. It is added up for all the units the producers sell. Total surplus is the sum of consumer surplus, producer surplus, and any tax revenue collected by the government.
Deadweight loss is the loss in total surplus due to an inefficient level of production.
Know the situations in which deadweight loss exists and how to find the deadweight loss graphically. Know how to depict a price ceiling and price floor graphically. Know how to find the deadweight loss in these situations, as well as evaulting the effect on consumer and producer surplus. A subsidy is the same as a negative tax.