Lesson: 13 x 7 = 28
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 Watch Abbott and Costello do some mathematical hocus pocus with multiplying 13 x 7 and getting an answer of 28.

Explain how Costello "cheated" with math to get that answer.
(If Youtube version is not available, try this link.)

Costello's Method
13

x7

---

21

 7

---

28
 Explanation
















Source: Original Version 1.0 developed at CIESE- 
Center for Innovation in Engineering & Science Education (2007)
Revised 11.11.21 currently under construction