Here’s a simple question: What is ten more than 73? 
Based
 on students’ responses, we learn something about their understanding of 
place value and our base ten number system. They might know it right 
away. They might have no idea and no strategy for figuring it out. They 
might want a paper and pencil in order to use a written algorithm, or 
they might count on their fingers. If their response isn’t quick and 
correct, they are poised to make an important conceptual leap.
There
 are many tools to help students understand place value and base ten. 
These include arrow cards, hundred charts, ten frames, and more. Here is
 a favorite from Sandi Stanhope and Loree Silvis. We’ve been using it in
 various classes and with individuals. It’s fast, easy, and you can 
carry it around in your back pocket (literally).
Rebekah Thomas, ELL and Math Teacher Extraordinaire and soon-to-be Vermont Mathematics Initiative graduate, shows you how here. Thank you, Rebekah!
