Section 2.1

1. Chapter 2 Section 2.1 Exercise #9

2. List the factors of the following number. 64 8 x 8 = 64 4 x 16 = 64 2 x 32 = 64 1 x 64 = 64 1, 2, 4, 8 , 16, 32, and 64 are all the factors of 64.

3. Chapter 2 Section 2.1 Exercise #13

4.   Which of the given numbers are prime? 0, 1, 15, 19, 23, 31, 49, 55, 59, 87, 91, 97, 103, 105 55 0  59 1  87 15    91  19 97 23   103 31   49 105  

5. Chapter 2 Section 2.1 Exercise #17

6. Which of the given numbers are divisible by 2? 45, 72, 158, 260, 378, 569, 570, 585, 3541, 4530, 8300 A number is divisible by 2 if its last digit is 0, 2, 4, 6, or 8. 45  570  72  585  158  3541  260  4530  378  8300  569 

7. Chapter 2 Section 2.1 Exercise #19

8. Which of the given numbers are divisible by 6? 45, 72, 158, 260, 378, 569, 570, 585, 3541, 4530, 8300 A number is divisible by 6 if it is an even number and the sum of the digits is divisible by 3. 45  570  5 + 7 + 0 = 12 72  7 + 2 = 9 585  158  1 + 5 + 8 = 14 3541  260  2 + 6 + 0 = 8 4530  4 + 5 + 3 + 0 = 12 378  3 + 7 + 8 = 18 8300  8 + 3 + 0 + 0 = 11 569 

9. Chapter 2 Section 2.1 Exercise #21

10. A school auditorium is to have 350 seats. The principal wants to arrange them in rows with the same number of seats in each row. Use the divisibility test to determine if it is possible to have rows of 10 seats each. Are 15 rows of seats possible? 350 is divisible by 10. 350 is not divisible by 15.