# Model Index

Trixie at 2 years, 8 months - Easy Addition - Trixie is playing with her xylophone, counting something on my T-shirt, when I see an opportunity to introduce an Easy Addition problem. "I have 5 fish over here, and 5 fish over here. What I want to know is how many fish I have altogether." (click here)

Trixie at 2 years, 11 months - Hard Subtraction 1 - Trixie is playing with a collection of toy Sesame Street characters. She has 5 Cookie Monsters and 3 Big Birds. She knows that she has more Cookie Monsters than Big Birds. Then I ask her, "how many more?" (click here)

Trixie at 3 years, 4 months - Easy Addition - Trixie knows that her school-age cousins get homework - worksheets with math problems. So Trixie wants homework also. (click here)

Trixie at 3 years, 4 months - Easy Subtraction - Suppose that you have 5 chickens and that you give 2 of them to me. How many chickens do you have left? (click here)

Trixie at 3 years, 4 months - Hard Addition - Suppose that I have 2 pennies. And suppose that you have 3 more pennies than I have. How many pennies do you have? (click here)

Trixie at 3 years, 4 months - Hard Subtraction 1 - I have 2 chickens and you have 5 chickens. How many more chickens do you have than I have? (click here)

Trixie at 3 years, 4 months - Hard Subtraction 2 - You have 4 chickens. You have 3 more chickens than I have. How many chickens do I have? (click here)

Trixie at 3 years, 8 months - Easy Multiplication - There are 3 people, and each person has 2 pigs. How many pigs are there altogether? (click here)

Trixie at 3 years, 9 months - Hard Subtraction 1 - I have 2 parts of a snake. You have 6 parts of a snake. Who has more parts of a snake - your or me? How many more do you have than I have? (click here)

Trixie at 3 years, 9 months - Hard Multiplication - I have 2 parts of the snake. You have 3 times as many parts as I have. How many parts do you have? (click here)

Trixie at 5 years, 8 months - Easy Subtraction - Suppose that you have 3 snakes and that someone gives you some more so that you now have a total of 7 snakes. How many snakes were you given? (click here)

Rose at 5 years, 8 months - Combinations (Multiplication) - You have 2 shirts and 3 pair of pants. How many different outfits can you make? (click here)

Rose at 5 years, 8 months - Easy Measurement - You have 12 candies and you would like to give 3 of them to each of your friends. How many friends can you give 3 candies to (click here)