Thinking Mathematically (6th Edition)

Published by Pearson
ISBN 10: 0321867327
ISBN 13: 978-0-32186-732-2

Chapter 5 - Number Theory and the Real Number System - 5.1 Number Theory: Prime and Composite Numbers - Exercise Set 5.1 - Page 256: 75

Answer

28 is a Perfect Number

Work Step by Step

By definition, a number is considered to be a perfect number if the sum of its factors (except the number itself) equals the number. The factors of 28 (excluding the factor 28 itself) are: 1, 2, 4, 7, 14. If we add those factors: 1 + 2 + 4 + 7 + 14, we get 28. This makes 28 a perfect number.
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