Numbers

Question 1

True or False: All Square and Cube roots of natural numbers that are not squares and cubes of natural numbers are irrational.

Answer 1

True

Question 2

An odd number can be expressed in the form:

Answer 2

2n - 1

where n is a natural number

Question 3

even + even =

Answer 3

even

Question 4

odd + odd =

Answer 4

even

Question 5

odd + even =

Answer 5

odd

Question 6

even*even =

Answer 6

even

Question 7

even*odd =

Answer 7

even

Question 8

odd*odd =

Answer 8

odd

Question 9

even^even =

Answer 9

even

Question 10

odd^odd =

Answer 10

odd

Question 11

even^odd =

Answer 11

even

Question 12

odd^even =

Answer 12

odd

Question 13

A number is divisible by 2, when its last digit is divisble by 2 or 0.

Answer 13

True

Question 14

A number is divisible by 3, when the sum of its digits is divisible by 3.

Answer 14

True

e.g. 675, 160791

Question 15

A number is divisible by 4 when the number formed by the last two digits is divisible by 4, or if they are 0.

Answer 15

True

7564, 6600

Question 16

A number is divisible by 5 when its last digit is 5 or 0.

Answer 16

True

e.g. 245, 50

Question 17

A number is divisible by 6, when it is divisible by 2 and 3 at the same time.

Answer 17

True

e.g. 354

Question 18

A number is divisible by 7 if the number of tens added to five times the number of units is divisible by 7.

Answer 18

True

e.g. 364 Number of tens 36, 5 times the number of units = 5*4 = 20, 36 + 20 = 56 is divisible by 7, so 364 is divisible by 7

Question 19

A number is divisible by 8 when the number formed by the last three digits is divisible is divisible by 8, or if they are 0.

Answer 19

True

e.g. 1000, 45677432

Question 20

A number is divisible by 9 when the sum of its digits is divisible by 9.

Answer 20

True

e.g. 432657

Question 21

A number is divisible by 10 when its last digit is 0.

Answer 21

True

e.g. 3480, 4870

Question 22

A number is divisible by 11 when the difference between the sum of the digits in the odd and even places is 0 or a multiple of 11.

Answer 22

True

Question 23

A number is divisible by 12 when it is divisible by both 3 and 4.

Answer 23

True

e.g. 252

Question 24

A number is divisible by 13 if the number of tens added to four times the number of units is divisible by 13.

Answer 24

True

e.g. 1248 Number of tens = 124, Four times number of units = 4*8 = 32. 124 + 32 = 156 which is divisible by 13. Therefore 1248 is also divisible by 13.

Question 25

A number is divisible by 15 when it is divisible by both 3 and 5.

Answer 25

True

e.g. 1350

Question 26

A number is divisible by 25 when the number formed by the last two digits is divisible by 25.

Answer 26

True

e.g. 657875.

Question 27

A number is divisible by 125 when the number formed by the last three digits is divisible by 125.

Answer 27

True

e.g. 87865750