Assignment no.-1
Playing with numbers
1. Which of the following is divisible by 3?
a) 24357806 b) 35796812 c) 34679345
2. Which of the following are multiple of 6?
a) 8790432 b) 63458924 c) 85492014
3. Which of the following are divisible by 11?
a) 14322341 b) 222222222 c) 1111111
4. Which of the following is a prime number?
a) 81 b) 87 c) 91 d) 97
5.Which of the following are co-primes?
a) 8,11 b) 9 ,10 c) 6,8 d) 15 ,18
2. The numbers13 and 31 are prime numbers . Both of these numbers have same digits 1 and 3 . Find such pairs of prime numbers up to 100.
3. Write seven consecutive composite numbers less than 100 so that there is no prime number between them.
4.A number is divisible by 3 and 8 both . By which other number will that number is always divisible?
5.The product of 3 consecutive numbers is always divisible by 6? verify this statement with help of some examples.
6. In each of the following numbers , replace * by the smallest number to make it divisible by 9
a) 2*135 b) 6678*1 c) 385*356
7. In which of the following numbers,replace * by the smallest number to make it divisible by 11
a) 467*91 b) 1723*4 c) 9*8071 d) 39*43
8. Express the greatest 5-digit number as product of primes.
9. What do you mean by perfect numbers ? write any 3 perfect numbers with proper verification.
10. write as many as as possible pairs of prime numbers less than 50 but more than 20 whose sum is divisible by 5.
11. verify that sum any two odd numbers is always multiple of 4.
12.Which of the following are prime numbers?
a) 193 b) 497 c) 253 d) 323
13. find the greatest 5- digit number which when divided by 20 ,24 , 45 leaves remainder 18 in each case.
14. find the smallest number which is when divided by 20,25,35 and 40 leaves a remainder of 14,19,29,34 respectively.
REFER DIFFERENT MATHEMATICS BOOKS AND DO MORE QUESTIONS BASED ON THIS CHAPTER.
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