Is 1998 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 1998 is composite or not first we have to find its factors.
Contents
Factors of 1998:
- If we have taken numbers from 1, 2, 3…for checking factors of 1998, we found that 1998 has factors 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998. Hence, we must say that 1998 is a composite number.
- Thus, 1998 is the composite number.
- If we multiply 1998 by 1, 2, 3 then we get the multiples of 1998 which are 1998, 3996 and so on.
About the number 1998:
- 1998 has more than two factors which are 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998 and hence it is the composite number.
- 1998 is the even composite number and it is not the perfect square also.
- If we divide 1998 by, 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998 then we get remainder as zero. Hence, 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998 are the factors of 1998.
Note:
- 1998 is not the perfect square.
- Factors of 1998: 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998
- Prime factors of 1998: 2, 3, 37
Conclusion:
- 1998 is the composite number which has factors 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998
- And hence, 1998 is not the prime number.
Multiple Choice Questions:
1) 1998 is a
a) Prime number
b) Odd number
c) Composite number
d) Both a and c
Ans: c) composite number
2) The non-prime factors of a composite number 1998 are
a) 1998
b) 2, 3, 37
c) 1, 6, 9, 18, 27, 54, 74, 111, 222, 333, 666, 999 and 1998
d) 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998
Ans: c) 1, 6, 9, 18, 27, 54, 74, 111, 222, 333, 666, 999 and 1998
3) 1998 is composite number because
a) It has factors 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998
b) It has only two factors
c) Divisible by 2
d) Both a and c
Ans: a) it has factors 1, 2, 3, 6, 9, 18, 27, 37, 54, 74, 111, 222, 333, 666, 999 and 1998