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. Donald D Ostrow

    June 18, 2021 - 5:22 am -

    Summer Greetings!

    I would love to continue receiving your blog, and would like to update my email address to
    “Don Ostrow” .

    I tried to go to WordPress to create an account to receive your dy/dan blog. The up front info says the first year is free and then it renews at $18/year. When I went to sign up it said that the first year is free, but it renews at $48/year. As a retired elementary math specialist, I am willing to afford the former prices but not the latter. Please advise.

    Love your stuff – have been a fan and a user for years. Thanks for your great work!

    • Hey Don, no charge for subscription. Just throw your email address in the box on this site that says “Subscribe” and you’ll start getting the emails when they drop. Thanks for the kind words.