You know those moments when you come up with a great idea WHILE you are in the middle of a lesson? I had one of those moments on Friday. I was sitting down to sing a counting song with my kiddos and the whole idea came to me about a way to help them visualize base ten concepts with the teen numbers. Frantically I put on a silly song for them to sing with each other and started cutting up index cards, writing numbers and drawing dots.
In my right hand I held up a big index cards with a 10 written on it and ten dots drawn underneath. We talked about what number was there and how many dots were on the card. Next I held up in my left hand a smaller card with the number 1 and 1 dot. We talked about the number and how many dots were there. Then I said "What if I did this" and pulled the cards together placing the 1 card on top of the 0 of the ten and the kids all yelled "11!" So I asked them "What if you wanted to WRITE 11, what would you do?" and they said 1 and 1" Then I said "What if you want to BUILD 11, what would you do?" They thought about it for a second and one said "Put a 1 with the 10" Bingo! So we did this over and over with all the numbers from 11-19. Each time I would ask the process for writing vs the process for building. I would also show them with the number cards how to bring the numbers together to build the number.
I have since made a nicer set of cards (the index cards and marker dots got ruined pretty quickly) and they are up for sale in my TPT store along with a student flap book to go along with the activity.
Click here to find it :)