Month over Month formula to show increase or decrease in rankings for SEO

I am trying to figure out a formula in excel for a month over month change in SEO rankings for each key word. I have in column B4 (which is for January) 54 and then in column C4 (for Feb.) 50 then in column D4 I would like to know the the difference either an increase or decrease. Ive tried =(C4-B4) which gives me just the difference but with SEO I want to show that I had an increase bc I went up 4 slots. And in other cases i went down slots. Ive tried conditional formatting as well. Any help would be greatly appreciated. Thank you!!!!