## Math Puzzles Topology

• #### Connected Loops

We challenge you to find a way to tie the three loops of string together so that untying any one of them causes the other two to be disconnected.

• #### The Seven Bridges of Königsberg

There are seven bridges in Königsberg. Can you cross each bridge just once without missing any of them?

• #### The FedEx Problem

Federal Express is a company that ships packages from one city to another by airplane. In the United States they use a system that might at first glance seem very odd and inefficient.

• #### The Four-Color Theorem

The small island nation of Seedonia is organized into three provinces: Sciville, Connexia, and Collabdale.

• #### The Lines Problem

Draw a continuous line made up of no more than four straight segments that goes through all of the nine dots.

• #### Trees in a Row

You have seven trees to plant. They need to be arranged in six rows with three trees in each row. How do you do it?

• #### More Trees in a Row

You have ten trees. Can you arrange them in four rows of five?

• #### Which Bike Is Free?

Bart, Chang, and Omar rode their bicycles to school. Each had a chain and a lock. Bart locked his bike to a lamppost and to Chang’s bike.