Less than three is a common way of forming a "<3" or heart symbol. It's used very often online and even more so among social networking, or instant messaging. A mathematic solution for less than three would be:

Solve for i

-3i+9u+9>9

-3i+9u>0

i-3u<0

i<3u

Online its a common way to refer to "love" by saying I <3 you, or I less than 3 you <3, because it looks like a formed heart. <3

It was a joke I started towards the "emo" kids in school. They put <3 signs on everything they can get their grimy little hands on. I started using it on myspace.com and now every emo kid in school has it written on every bathroom stall in the school.