I think of this as a "hands-on" problem. I have 40 pure white paper rabbits. I also have 74 brown stickers I can put on the rabbits, either one or two stickers on each rabbit.
I start by putting one sticker on each rabbit to give it one brown spot. How many stickers (spots) do I have left? If I then start to put a second sticker on each rabbit how many rabbits are left when I run out of stickers?