Geoff Krall Combs The Internet For Lesson Plans So You Don’t Have To

If the deluge of interesting problem-based material on the Internet overwhelms you, as it does Jonathan Claydon, Geoff Krall’s curriculum maps are a great place to start. He’s taken the Common Core’s scope and sequence documents and combed the Internet for items that fit. He’s included a few of my own items, some items from the Shell Centre, along with a lot of great lesson ideas I’d completely forgotten. Bookmark it. Throw him some love in the comments.

I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.


  1. I had seen Geoff’s offering on Thursday and immediately shared it with the teachers with whom I work. It’s an excellent, much-needed contribution to and resource for US math teachers, regardless of one’s opinion (mine is mostly negative) of the Common Core. Hats off to Geoff.

  2. I’d say his efforts here are worth at least r = 5 – 5 sin theta. Didn’t someone also compile a long list of project based learning material for various courses? I have no idea if I’m making that up or if I just lost the link.

    I want to add that what I said was meant to be positive. After absorbing the things I’ve seen other people do it has jump started my own creativity to new heights. I find it hard to decide between Awesome Project A and Awesome Project B on a number of occasions.

  3. “Pick a number. Say 25. Now break it up into as many pieces as you want. 10, 10, and 5, maybe. Or 2 and 23. Twenty-five ones would work. Now multiply all those pieces together. What’s the biggest product you can make? Pick another. What’s your strategy? Will it always work? [Malcolm Swan]”

    This is an amazing question. Has anyone done this with kids?

    Christopher Danielson posted a video of something similar: One student selected a number, and then another had to take that number and make 20. It was fun to watch the kids so intellectually engaged.

    I’d love to see one of the Danielson children take on the Swan question (or some modification of it) with Dad facilitating.

  4. Sean:
    I think the problem should be limited to positive numbers only, otherwise:



  5. Whoa! I’m pretty lost with the higher level math work (r = -1- sin(theta) HUH!?) but I love puzzling over math problems. I teach kindergarten and I’m always on the look out for some great number talk ideas. Developing mathematical thinking in the early years will prepare the kids for more difficult questions throughout their school years.

  6. @Jim,

    No need to limit the students’ creativity. If a student actually comes up with an answer that uses negatives, as you suggest, then you can limit it to positive integers…but no need to limit the creativity before. Invite them to think outside the box!