One cold, December night,

Sue awoke from her slumber with fright.

She just realized, to her dismay,

She forgot to write Santa a letter yesterday!

The first thing she thought after waking from her rest

Was that she really needed to pass her AP Econ test!

She considered asking for a three or four, but had too much drive,

So Sue wished for her very first five!

When Santa's elves read the note,

They went to the big man, and started to quote,

"Dear Santa, you see,

A five on AP Econ is what I really need."

As Santa walked and scratched his head,

The elves followed as he led.

"We need to teach Sue about supply and demand,

And then get back to the other requests at hand!"

One elf jumped up and down in the back,

"Econ is one thing for which I always had a knack,

Let me go teach Sue exactly what I know,

And be back just in time for the snow!"

Santa agreed to let Sam the Elf go,

And such exciting news made Rudolph's nose glow!

Rudolph was ready and eager to teach

Supply and demand, oh, what a treat!

Sue looked out her window and saw

Sam the Elf and Rudolph, just staring in awe.

"Sue, are you ready to learn

So we can leave before the night begins to turn?"

With such short time to learn, Sue listened up

To the elf and his reindeer, who stood behind as backup.

“We’ll start off with demand,

As the price decreases,” Sam said, waving his hand.

“The quantity increases,” he said with glee,

“This means that they vary inversely.

If only the price changes,

The point’s movement ranges

Only to other spots on the curve,”

Sam showed as Sue observed.

“But if certain events occur,

The current curve starts to blur,

So a new curve must be drawn.”

“What events?” Sue yawned.

“Take hot chocolate, for instance,”

Sue eagerly listened for Sam’s assistance,

“If the price of marshmallows goes down,

The demand curve would?” Sam asked, but Sue just frowned.

Sam said, “The demand curve would shift right,

Since they’re complements. It may be confusing, but just sit tight!

But if the price of hot cocoa gets lower,

The demand for eggnog, a substitute, is slower.

This means the demand curve for eggnog goes left,”

Sue groaned and interrupted, “I want to experience the sweet kiss of death!”

Sam laughed, “Just remember IRDL,

Increase, right, decrease left, IRDL the Turtle.”

Sue tried, “If people expected there to be two feet of snow,

Everyone would stock up on lots of cocoa.

The demand curve would then shift right.”

In that moment, Sue swore her five was in sight!

“This isn’t so bad!” She said in reply.

“Sue, we still have to go over supply.

Just like demand, if only price changes

The point only ranges

On the exact same curve.

But like demand, there are certain exceptions to know.

The first one being pretty easy to show

As price increases, demand does too

This means that they are directly related, who knew!

Now, let’s say the price of sugar gets low,

Producers can buy more, so..."

“The curve shifts right-"

"Do you understand?” “I think I might!”

“If the government decided to put a tax on hot cocoa

The supply curve would go left, come on, you know!”

Sue decided to try herself,

Explaining the effect of technology to the elf.

“If Santa’s elves make a new machine

That makes twenty hot chocolates instead of eighteen,

The supply curve goes right,”

Rudolph was so excited with Sue’s progress he took flight!