from the federal budget. we have heard this story before. billions of dollars are at stake as you know but do lawmakers know what they're fighting over? actually, do you? jessica yellin has the results of a fascinating budget iq test. >> reporter: on capitol hill, they're on the verge of a government shutdown. because congress wants to slash federal spending. but republicans and democrats can't agree on how much to cut. the biggest fights are over just a handful of programs including -- >> foreign aid. >> npr. >> food stamps. >> reporter: if trimming those programs rein in spending may must make up a huge part of the federal budget. right? that's what most americans think. what percentage of the federal budget we spend on foreign aid? >> 40%. >> foreign aid? 20%. >> reporter: a new cnn/opinion research poll finds most