Number Series


Direction: What will come in the place of question mark (?) in the following number.

  1. –1, 0, ?, 8, 15, 24
    1. 4
    2. 3
    3. 2
    4. 1
    5. None of these

  1. View Hint View Answer Discuss in Forum

    The number pattern is described in the below image.It is clear that we are getting the next terms on adding + 1 , + 3 , + 5 , + 7 , + 9 in previous term respectively.
    First term = - 1
    Second term = First term + 1
    Third term = Second term + 3
    Similarly we can calculate the all others terms

    Correct Option: B

    The number pattern is described in the below image.
    As per figure we can see the number series is in specific pattern which will help us to find the next number.
    It is clear that we are getting the next terms on adding + 1 , + 3 , + 5 , + 7 , + 9 in previous term respectively.
    First term = - 1
    Second term = First term + 1
    Second term = -1 + 1 = 0
    Third term = Second term + 3
    Third term = 0 + 3 = ( ? )
    ∴ ( ? ) = 3
    Similarly we can calculate the all others terms
    Fourth term = 8
    Fifth term= 15



  1. 1, 2, 6, 24, ? ,720
    1. 3
    2. 5
    3. 120
    4. 8
    5. None of these

  1. View Hint View Answer Discuss in Forum

    As per given series , we can see that
    First term = 1
    Second term = First term × 2 = 2
    Third term = Second term × 3 = 6
    Similarly we can calculate the all others terms

    Correct Option: C

    As per given series , we can see that
    First term = 1
    Second term = First term × 2
    Second term = 1 × 2 = 2
    Similarly we can find the all others terms
    Third term = Second term × 3
    Third term = 2 × 3 = 6
    Fourth term = Third term × 4
    Fourth term = 6 × 4 = 24
    Fifth term = Fourth term × 5
    Fifth term = 24 × 5 = ?
    ∴ ? = 120
    Sixth term = Fifth term × 6
    Sixth term = 120 × 6 = 720



  1. 251, (12), 107, 381, (?) , 125
    1. 14
    2. 24
    3. 11
    4. 16
    5. None of these

  1. View Hint View Answer Discuss in Forum

    The given series is in the below pattern,we can see that
    Square root of ( First term - Third term ) = Second term
    ⇒ Square root of ( 251 – 107 ) = Square root of 144 = 12 = Second term
    Square root of ( Fourth term - sixth term ) = Fifth term
    ⇒ 381 – 125 = Square root of 256 = 16 = Fifth term

    Correct Option: D

    The given series is in the below pattern,we can see that
    Square root of ( First term - Third term ) = Second term
    ⇒ Square root of ( 251 – 107 ) = Square root of 144 = 12 = Second term
    Square root of ( Fourth term - sixth term ) = Fifth term
    ⇒ 381 – 125 = Square root of 256 = 16 = Fifth term
    Fifth term ( ? ) = 16
    Hence, 16 is the missing number in the given question.


  1. 3120, ?, 122, 23, 4
    1. 488
    2. 621
    3. 610
    4. 732
    5. None of these

  1. View Hint View Answer Discuss in Forum

    As per above given series , we can see that
    Descending order of given series -
    Next term = ( 5 x previous term ) + odd number ( which starts 3 )
    Here , 5th term = 4
    4th term = 5 × 5th term + 3 = 5 × 4 + 3 = 23
    3rd term= 5 × 4th term + 7 = 5 × 23 + 7 = 122
    Similarly , we can calculate all others terms also.

    Correct Option: B

    As per above given series , we can see that
    Descending order of given series -
    Next term = ( 5 x previous term ) + odd number ( which starts 3 )
    Here , 5th term = 4
    4th term = 5 × 5th term + 3
    4th term = 5 × 4 + 3 = 23
    3rd term= 5 × 4th term + 7
    3rd term= 5 × 23 + 7 = 122
    Similarly , we can find all others terms also.
    2nd term = 5 × 3rd term + 11
    2nd term = 5 × 122 + 11 = ?
    ? = 621
    1st term = 5 × 2nd term + 15
    1st term = 5 × 621 + 15 =3120