Broken Calculator: 2-Digit Addition

Rounding Numbers (But Not To 10)

What could we possibly do to make rounding more interesting for students who already get it? In this series, students consider how they might round to values other than “the nearest 10.” How, for example, do we round to the nearest 9? 7? 15?

Math Curiosity: Palindromic Number Conjecture

Using this one weird trick, it seems that you can turn any number into a palindrome!