Numbers

Question 1

Places in number system

Answer 1

10 crore (10^8),1 crore(10^7), 10Lakh(10^6), 1Lakh(10^5), 10 thousand(10^4), Thousand(10^3), Hundred(10^2), Tens(10), Unit(1)

Question 2

Place value
Face value

Answer 2

Place-unit considered
Face-digit itself

Question 3

0 is neither positive nor negative integer

Answer 3

True

Question 4

How to check if a number is prime

Answer 4

Find its square root, then take a no.-k which is nearly greater than its root, check that all prime numbers less than k do not divide the number

Question 5

Composite number

Answer 5

Number greater than 1 which are not prime

Question 6

1 is neither prime nor composite

Answer 6

True

Question 7

Co prime nos.

Answer 7

If HCF is 1

Question 8

Co prime property

Answer 8

If a no. is divisible y both p and q and are co prime then it means that the no. is divisible by pq

Question 9

divisibility by 2
4
8
16

Answer 9

2-Unit digit should be even or divisible by 2
4-last 2 digits should be divisible by 4
8-last 3 digits should be divisible by 8
16-last 4 digits should be divisible by 16

Question 10

divisibility by 3
9

Answer 10

3-sum of digits divisible by 3
9-sum of digits divisible by 9

Question 11

divisibility by 5
10

Answer 11

5-unit digit 5 or 0
10-unit digit 0

Question 12

divisibility by 6

Answer 12

divisible by 2 & 3

Question 13

divisibility by 11

Answer 13

sum of digits at its odd places- sum of digits at even places = 0 or divisible by 11

Question 14

divisibility by 12
14
24
40
80

Answer 14

12-divisible by 4,3
14-7,2
24-3,8
40-5,8
80-5,16