Goodstein’s unprovable theorem

Recently I learned about a family of sequences of nonnegative integers (called Goodstein sequences) and two remarkable theorems about these sequences. Begin with any positive integer . This is the first term in the sequence. For example, suppose we begin with . The first step in computing the second term of the sequence, , is…

Kindergarten Mathematics (part 2): a report

Last week I wrote a blog post asking for suggestions for math to present to my son’s kindergarten class. My readers posted many great comments. Thank you all. Today was the big day,… and it was a great success! I began by talking about what I do. My son introduced me as a math teacher….