Challenge Four

Counting Bones

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            Your students should use the following information to create math problems suitable to their present level of achievement.  They can exchange their problems for their regular class work or the teacher can use them for testing.  If used for a test, the test should include extra problems so the students whose problems were used cannot answer their own questions.


Bones make up the body’s scaffolding system.  They are the structures that hold up the body, provide protection for body parts, and provide places of attachment for internal organs.  They also produce blood cells and store calcium and other minerals for use in the body.


A newborn baby has 350 bones.  Many of these bones fuse so a twenty five year old adult has 206 bones.  One out of twenty humans has an extra rib and these people are more likely male than female.  Sixteen percent of Eskimo men have an extra rib.

While students are learning the names and functions of the bones in the human adult skeleton, they can use the number of bones for doing mathematical problems.  Adults have the following number of bones.¹

Arms and hands






Legs and feet


Pectoral girdle














1.      What per cent of an adult’s bones are hip bones? 

2.      Make two different graphs to show the distribution of bones in the human skeleton.  Make them on the computer if possible.



Try to have your students generate questions that can be answered mathematically.  Some examples are given.  Use these questions only if needed as an example. 

  • Students design their own problems.  They can use the information provided plus the extra bone information they research.

  • Students can measure the size of hands of everyone in the class and create new math problems with that information.  They can determine the ratio between the size of hand and the height of each student.

  • Is that ratio equal to the ratio for the youngest (or oldest) students in the school?

  • Are both feet equal in length?

  • Use a picture of a skeleton.  What bones show symmetry?

  • Are any two fingers of the same hand the same length?

  • Are both feet the same length?

  • Are any bones mirror images of one another?  If “yes”, which ones?


©2010 Elinor W. Semel   All rights reserved.
¹McCutcheon, Marc, The Compass in Your Nose and Other Astonishing Facts about Humans, 1989, Jeremy P. Tarcher, Inc., Los Angeles, p. 129