# 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)