Is 780 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 780 is composite or not first we have to find its factors.
Contents
Factors of 780:
- If we have taken numbers from 1, 2, 3…for checking factors of 780, we found that 780 has factors 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780. Hence, we must say that 780 is a composite number.
- Thus, 780 is the composite umber.
- If we multiply 780 by 1, 2, 3 then we get the multiples of 780 which are 780, 1560 and so on.
About the number 780:
- 780 has more than two factors which are 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780 and hence it is the composite number.
- 780 is the even composite number and it is not the perfect square also.
- If we divide 780 by 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780 then we get remainder as zero. Hence, 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780 are the factors of 780.
Note:
- 780 is not the perfect square.
- Factors of 780: 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780
- Prime factors of 780: 2, 3, 5, 13
Conclusion:
- 780 is the composite number which has factors 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780
- And hence, 780 is not the prime number.
Multiple Choice Questions:
1) 780 is a
a) Odd number
b) Prime number
c) Composite number
d) Both b and c
Ans: c) composite number
2) The prime factors of a composite number 780 are
a) 1
b) 2, 3, 5, 13
c) 1, 4, 6, 10, 12, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780
d) 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780
Ans: b) 2, 3, 5, 13
3) 780 is the composite number because
a) It has factors 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780
b) It has only prime factors
c) Divisible by 2
d) Both a and b
Ans: a) It has factors 1, 2, 3, 4, 5, 6, 10, 12, 13, 15, 20, 26, 30, 39, 52, 60, 65, 78, 130, 156, 195, 260, 390 and 780