Chapter 6 - Section 6.1 - The Basics of Counting - Exercises - Page 398: 53

33 integers

Number of integers $\leq$100 which are multiple of 4 = 25 Number of integers $\leq$100 which are multiple of 6 = 16 Number of integers $\leq$100 multiple of 12 = 8 {a number multiple of both 4 and 6 is a multiple of 12} Hence numbers $\leq$100 which are multiple of 4 or 6 = 25 + 16 - 8 = 33 {using De Morgan's law}