Saturday, September 5, 2015

Commas Have Names... use them.

 Large numbers can be hard for students to read.  They stumble with the place value names, and can be intimidated by the large number of columns. I reassure them that the numbers are easy to read if you know the names of the commas.  Each comma has its own name based on position. The name doesn't change, so you only need to know how to read numbers into their hundreds if you know the names of the commas.  
The first two commas you'll see in a number are named "thousand"  and "million", followed by "billion" and "trillion", etc... 

This approach always makes sense to my students.  They don't see large numbers that often, and feel in command when they can easily read:
forty-two "million"  three hundred forty-two "thousand" seven hundred eighty-three

Give it a try.  See what how it goes.


1 comment:

  1. Cool. Next up, you can tell them about K ("from the Greek χίλιοι ('khilio')" according to Wikipedia, meaning thousands, and M (mega) for millions, as in 5K for 5,000 and 2M for 2,000,000. Then there's MM for a million million meaning a billion, and a thousand thousand meaning a million. You can see how Microsoft uses this to show file sizes in Windows Explorer. Fun stuff.