So he started with 3/4 lb and ended up with 2/3 of that so 2/3 of 3/4 'of' can be roughly translated as multiply so 2/3 times 3/4 =6/12=1/2 lb left or you know that there are 3 out of 4 parts pound left so 2 out of 3 parts of nuts is = 2/4 or 1/2 lb
A residual is a measure of how well a line fits an individual data point. Testing the two other points can really help to see how well the line fits.
