Need help with name of online puzzle?

There is a puzzle game I use to play where you have a grid and there are number all over it. You have to connect the numbers so they make sense, for example you have a 3 and it must connect to another 3 using only 3 squares. When you are all finished it will make a picture if you did it right. Does anyone know what these puzzles are called and a good site I could play them on?Need help with name of online puzzle?
Puzzle Games

trade in value

google crome