We've been working on understanding and using the hundreds chart in kindergarten. Even when I taught first grade I found that students frequently confused the teen numbers with 40, 50, 60, etc. I always made a big deal of being silly when saying these numbers- an old voice for a number ending with 0 and a higher pitched teenage voice for a teen number. When kids say a number I ask, "Is that a teenager number or an old number" and have them repeat it so it is clear.
Today, in the midst of a rousing game of Magic Number (everyone stands in a circle and counts off a set amount of numbers- today we were counting from 10 to 20. Any time someone gets the "magic number" (today was 20) that person has to sit down. It's amazing how frequently they can play the game and never get tired of it...)
At first they were saying their 13s and 14s in a way that sounded very similar to thirty and forty. I did my little teenager number vs old number, but this time added in, "you know, a teenager like Justin Bieber".
Shrieks. As though Justin Bieber himself just entered the room.
I momentarily regretted the reference. But then the strangest thing happened. As the game went on every single child very clearly stated their numbers, with no confusion. The girls did it with giggles, as though they were invoking Bieber in the mere mention of a number close to his age. As much as the Bieber-craze pains me I have to admit I appreciate an easy teaching point.