This video lesson from Khan Academy explains the differences between a change in the quantity demanded for a good (which causes a movement along a demand curve) and the change in a good's demand (which causes the entire demand curve to...

We've learned about demand for a good or service, but aggregate demand is different: it's the demand for everything bought in an economy. In this video, we discuss how aggregate demand (AD) is different from demand and why aggregate...

In this video, we introduce the concept of consumer surplus as the difference between marginal benefit and price paid. [5:01]

When a demand curve is linear, calculating consumer surplus becomes relatively simple: calculate the area of a triangle. In this video we walk through calculating consumer surplus.