Ariel has 42 stamps, and her brother Axel has 29 stamps. How many more stamps does Ariel have than Axel? [1] First I guess I’ll build Ariel’s collection. It’s in Blue: [2] Next I think I’ll build Axel’s collection. It’s in Red:

[3] My plan now is to dump all their stamps in one place and then maybe I can find out what they have that is the same-looking. Here’s all their stamps together: [4] I have an idea on how I can mark the pieces I see that are the same for Ariel (Blue pieces ) as for Axel (Red pieces ). My idea is, I will link the “same pieces” with a Green cord like this:

[5] So, below, using Green cords ( ), I’ve linked the pieces that I can see both Ariel and Alex have: [6] I’d feel better if I moved the “linked pieces” over to the side (it’ll help me see things more clearly), so I’ll do that next…

[7] Ok, so my “linked pieces” are the ones where Arial and Alex have the same stuff, and those are over on the left… [8] Looking at the “unlinked pieces”, I see some Red square pieces that would love very much to be linked to some Blue square pieces. But the Blues are all glued together in a stick, so I will trade one Blue stick for ten Blue squares. My idea is: Trade For

[9] My Purple arrow shows where I took out the one Blue stick and replaced it with ten little Blue square pieces… [10] Now I feel ready for my fantastic Green “linking cord” to grab some more pieces that look the same (that is, pieces that both Alex and Ariel have). Let’s do it!

[11] Yayy! I was able to link all the Red squares to some Blue squares! [12] Now I’ve forgotten what the question was… Oh yes, I’m looking for who has more, and how much more. Right. Well, there are some Blue pieces that aren’t linked to the Red pieces. I’m going to put some Check Marks by those pieces…

[13] Below, I’ve checked the pieces that weren’t linked to any others… [14] My thinking now is this: The “linked pieces” means to me that no one has any more than the other person. For example, Alex has a Red square, Ariel has a Blue square. But the “unlinked pieces” (with the check mark ) are pieces that Ariel has but Alex does not. So I’m thinking that Ariel has this much more: (...Which is 13 more stamps)