My little guy can count to a million if I really let him except he can not count the teens. Every other number 0-12 and 20 on up he can get perfectly. But it then goes... 13, 18,19,15, 19 20! He's only 3 so I'm not worried, he'll eventually get it... but, is there any tips and tricks besides repetition and counting everything in sight that helps? We sing songs, count EVERYTHING in sight, play games where he has to count. I think he's just being stubborn with the teens lol. He can write his numbers just fine and he can put pictures of hte numbers in the correct order and knows them by sight too. I just need some fresh ideas before I go insane.
Have you tried having him count while he is walking around or walking up the steps? Or maybe even try doing a jumping jack game and see if that doesn't click for him. Play the game of how many numbered colors you can count in a color counting game. Then make sure you have how ever many numbers of colors in the teens laying about just so that he can count them. But not too much more than that amount though as you want those particular numbers to stick in his mind.