I have been reading from this textbook which talks about CPI and inflation
http://faculty.washington.edu/cnelson/Chap04.pdf
On pages 5 and 6, it talks about how they are deflating the nominal income using the CPI. But in page 6, they work out the percentage difference in real income between two years, and they state that is the net difference of her increase in real income and inflation
But I thought using the CPI was getting rid of the effect of inflation? What am I not undersranding?