These magnetic number lines are AWESOME! The blue number line comes in two pieces with 0-10 on one and 11-20 on the other and this is PERFECT for us as we are just beginning to introduce the number line and are really focusing in on 0-10 right now. The entire back of the number lines is magnetic so it stays put. I love that we can write on it and practice simple addition and subtraction in a very hands on way and kinesthetic way. We use it on the magnetic board and off the board. I have not used the other number lines but I like that it includes two blank number lines. These are so versatile. We will be using these for a long time on our homeschooling journey.