Basic Computer Knowledge Test Questions and Answers

Number System : Aptitude Test (200 Questions with Explanation)

  • Formulas:-
    0, 1, 2, 3, ----9. are called digits.
    10, 11, 12,----- are called Number.

    Natural number (N) :-
    Counting numbers are called natural numbers.
    Example:- 1, 2, 3,---etc. are all natural numbers. minimum natural number 1 and maximum natural number ∞

    Whole numbers (W) :-
    All counting numbers together with zero from the set of whole numbers
    Example:- 0, 1, 2, 3, 4, ------ are whole number.

    Integers (Z) :-
    All counting numbers, 0 and -ve of counting numbers are called integers.
    Example:- -∞---------, -3, -2, -1, 0, 1, 2, 3, -------∞

    Rational Numbers (Q) :-
    A Rational Number is a real number that can be written as a simple fraction
    Example:- {p/q/p,q∈Z}

    Irrational NUmbers :-
    An Irrational Number is a real number that cannot be written as a simple fraction.
    Example:- √

    Even numbers :-
    A number divisible by 2 is called an even number.
    Example:- 0, 2, 4, 6, - - - - - - - - -

    Odd numbers :-
    A number not divisible by 2 is called an odd number.
    Example:- 1, 3, 5, 7, - - - - - -

    Composite Numbers :-
    Numbers greater than 1 which are not prime, are called composite numbers.
    Example:- 4, 6, 8, 9, 10, - - - -. 6 -> 1,2,3,6.

    Prime Numbers:-
    A number greater than 1 having exactly two factors, namely 1 and itself is called a prime number. Upto 100 prime numbers are:
    2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 71, 73, 79, 83, 89, 97

    Co-prime Numbers:-
    Two natural numbers a and b are said to be co-prime if their HCF is 1.
    Example:- (21, 44), (4, 9), (2, 3), - - - - -

    Twin prime numbers :-
    A pair of prime numbers (as 3 and 5 or 11 and 13) differing by two are
    called twin prime number.
    Example:- The twin pair primes between 1 and 100 are
    (3, 5), (5, 7), (11, 13), (17, 19), (29, 31), (41, 43), (59, 61), (71, 73).

    Face value:-
    Face value is the actual value of the digit.
    Example:- In the number 7635, the "7" has a face value of 7, the face value of 3 is 3 and so on

    Place value:-
    The value of where the digit is in the number, such as units, tens, hundreds, etc.
    Example:- In 352, the place value of the 5 is "tens"
    Place value of 2 * 1 = 2;
    Place value of 5 * 10 = 50;
    Place value of 3 * 100 = 300.

1.

What is the place value of 7 in the numeral 2734? 

   A.) 70
   B.) 7
   C.) 700
   D.) 7.00

Answer: Option 'C'

7 × 100 = 700

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