Math Brain Teasers
Work with a small group (no more than 3) to try and solve the story problems listed below.  You may use a pen and paper and the online calculator listed as well.  Good Luck!

online calculator:  http://www.online-calculator.com/

Grandmas & Trolls

You are on your way to visit your Grandma, who lives at the end of the valley.
It's her birthday, and you want to give her the cakes you've
made.

Between your house and her house, you have to cross 7 bridges, and
as it goes in the land of make believe, there is a troll under every bridge!
Each troll, quite rightly, insists that you pay a troll toll. Before you can
cross their bridge, you have to give them half of the cakes you are carrying,
but as they are kind trolls, they each give you back a single cake.

How many cakes do you have to leave home with to make sure that you arrive at
Grandma's with exactly 2 cakes?

Monk Steps

A monk has a very specific ritual for climbing up the steps to the temple. First
he climbs up to the middle step and meditates for 1 minute. Then he climbs up 8
steps and faces east until he hears a bird singing. Then he walks down 12 steps
and picks up a pebble. He takes one step up and tosses the pebble over his left
shoulder. Now, he walks up the remaining steps three at a time which only takes
him 9 paces. How many steps are there?

Firefighter

A firefighter stood on the middle rung of a ladder, spraying water on a burning
house. He then climbed up 6 rungs before the heat of the flames caused him to
come down 10 rungs. After some minutes he was able to climb 18 rungs to the very
top of the ladder. How many rungs did the ladder have?

Farm Animals

Your objective is to buy exactly 100 farm animals with exactly 100 dollars. You
must buy at least 1 of each animal. You may need some paper!

The
Costs:
Cows: $10 each
Pigs: $ 3 each
Chickens: $0.50 each