Is 78 is a composite number or not ?
- As we already know that, the number having factors 1 and the number itself is the prime number.
- And numbers having more than these two factors are the composite numbers.
- To check whether the number 78 is composite or not first we have to find its factors.
Contents
Factors of 78:
- If we have taken numbers from 1, 2, 3…for checking factors of 78, we found that 78 has factors 1, 2, 3, 6, 13, 26, 39 and 78. Hence, we must say that 78 is a composite number.
- Thus, 78 is the composite number.
- If we multiply 78 by 1, 2, 3 then we get the multiples of 78 which are 78, 156, and so on.
About the number 78:
- 78 has more than two factors which are 1,2, 3, 6, 13, 26, 39and 78 and hence it is the composite number.
- 78 is the even composite number and it is not the perfect square also.
- If we divide 78 by 1, 2, 3, 6, 13, 26, 39 and 78 then we get remainder as zero. Hence, 1, 2, 3, 6, 13, 26, 39 and 78 are the factors of 78.
Note:
- 78 is not the perfect square.
- Factors of 78: 1, 2, 3, 6, 13, 26, 39 and 78
- Prime factors of 78: 2, 3, 13
Conclusion:
- 78 is the composite number which has factors 1, 2, 3, 6, 13, 26, 39and 78.
- And hence, 78 is not the prime number.
Multiple Choice Questions:
1) 78 is a
a) even number
b) Prime number
c) Composite number
d) Both a and c
Ans: d) both a and c
2) The prime factors of a composite number 78 are
a) 1
b) 2, 3, 13
c) Both a and b
d) 781
Ans: b) 2, 3, 13
3) 1 is the not prime factor of 78 because
a) It is the prime number
b) 1 is neither prime nor composite number
c) Both a and b
d) Given statement is false
Ans: b) 1 is neither prime nor composite number