Quizz On Group theory and numbers

Which of the following group of order is abelian?

• 10

• 8

• 5

• 24

Z set of all positive integers which of the following operation will represent a group

• a*b=a+b+2

• a*b=2a+b

• a*b=(a+b)/2

• a*b=a²+b

which of the following is prime number?

• 2

• 9

• 15

• 21

All Prime numbers are odd.

• True
• False

which of the following groups of order is abelian?

• 9

• 11

• 221

• 15