Linking Bridges

In this week’s puzzle students are presented with a page showing several islands that are all numbered. The challenge is to connect all of the islands with bridges so that the number on the island corresponds to the number of bridges going to it or from it. Additionally, other rules must be followed, including that no bridges intersect or cross over islands.

While this puzzle can largely be solved by trial-and-error, there are elements of logical thinking involved as well. For example, two islands that each have one bridge cannot be connected to each other because this would prevent them from being connected to the other islands, which is one of the requirements. To allow students to explore possible solutions without constantly drawing and erasing lines, provide them with flat toothpicks and/or coffee stirrers cut to various lengths. This will allow them to lay bridges and rearrange them before recording their solutions. Once they are sure they have a solution that is valid, they can draw it in on the small version of the puzzle provided.

The three puzzle pages provided give challenges with varying levels of difficulty and should be done sequentially. In addition to allowing students to solve puzzles, this activity provides the opportunity for students to be puzzle designers. A blank grid page is provided on which students can design their own versions of the puzzle. These can be traded with classmates to be solved and taken home to be shared with family.

Click on each page to download.
LingkingBridge2LinkingBridge3

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Solutions

Click the arrow below to view the solutions.

In Linking Bridges, students were challenged to connect islands with bridges so that the number of bridges going to each island corresponded to the number written on that island. Additionally, bridges could not cross, go through islands, or go diagonally, and there could not be more than one bridge between the same two islands. The solutions are shown here.

LinkingBridgesSols

Dave Youngs

Dave Youngs is director of the Graduate Math/Science Education program at Fresno Pacific University. In this position he works with both pre- and in-service teachers in the areas of math and science education. He is most interested in the elementary and middle school levels.

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