# Modeling - Hard Subtraction 1

Trixie was 3 years and 4 months old at the time that this video was
made.

**The Problem**

Trixie had just easily modeled an Easy Subtraction problem so I decided
to
try a Hard Subtraction 1 problem. The problem is, "I have 2 chickens
and you
have 5 chickens. How many more chickens do you have than I have?"

**What To Look For In This Video**

- Trixie has no problem setting up the model. That is, she easily gives me 2 blocks and easily counts out 5 blocks for herself.
- She has no problem when I ask her "who has more?"
- I was so surprised that she knew that she had 3 more that I asked her to prove it. Her response convinced me that either she had a temporary flash of understanding - or had simply made a lucky guess.
- Trixie doesn't seem to clearly understand the distinction between
a)
**how many**chickens she has and b)**how many more**chickens she has. This misunderstanding is very typical. - I showed her how my 2 chickens match up with 2 of hers, and how she has 3 extras.
- It is interesting to compare Trixie's work on this Hard Subtraction 1 problem with her work on Easy Subtraction and her work on Hard Subtraction 2. All 3 of these problems were presented to her in one sitting.