In this activity, students will follow and then analyze work by mathematician and fencing master Ludolph Van Ceulen (1540-1610) on adding similar radical numbers, like . His method is quite different from the method currently in use in the secondary school curriculum and College Algebra, in that he does not first simplify the square root expressions before adding them. This activity could be used with high school or College Algebra students after they have learned the current method, in order to reinforce their understanding of radicals. The activity would also be appropriate to use with pre-service mathematics teachers or in a history of math class or in a math circle. It demonstrates that there may be more than one algorithm or technique for performing arithmetic operations, and that mathematics, including arithmetic, develops and evolves over time.
Huffman, Cynthia J. Ph.D., "A Historical Activity Adding Irrational Numbers" (2020). Faculty Submissions. 1.