Mathematical operation and symbol notation


Direction: If the given interchanges are made in signs and numbers, which one of the four equations would be correct?

  1. Given interchanges signs 'x' and '÷'; numbers '4' and '9'
    1. 94 x 7 ÷ 47 = 324
    2. 94 x 7 ÷ 97 = 329
    3. 49 x 7 ÷ 49 = 7
    4. 47 x 9 ÷ 94 = 18

  1. View Hint View Answer Discuss in Forum

    (a) 49 ÷ 7 x 97 ≠ 324
    (b) 49 ÷ 7 x 47 = 329
    (c) 94 ÷ 7 x 94 ≠ 7
    (d) 97 ÷ 4 x 49 ≠ 18

    Correct Option: B

    (a) 49 ÷ 7 x 97 ≠ 324
    (b) 49 ÷ 7 x 47 = 329
    (c) 94 ÷ 7 x 94 ≠ 7
    (d) 97 ÷ 4 x 49 ≠ 18


  1. Select the correct combination of mathematical signs to replace * signs and to balance the following equation
    8 * 8 * 1 * 7 = 8
    1. x ÷ +
    2. + ÷ x
    3. ÷ x +
    4. + x ÷

  1. View Hint View Answer Discuss in Forum

    From option (c),
    8 * 8 * 1 * 7 = 8
    ⇒ 8 ÷ 8 x 1 + 7 = 8
    ∴ 8 = 8

    Correct Option: C

    From option (c),
    8 * 8 * 1 * 7 = 8
    ⇒ 8 ÷ 8 x 1 + 7 = 8
    ∴ 8 = 8



  1. If '+' denotes ÷ , '-' denotes x, 'x' denotes - and '÷' denotes +, then
    35 + 7 - 5 ÷ 5 x 6 = ?
    1. 36
    2. 24
    3. 20
    4. 14

  1. View Hint View Answer Discuss in Forum

    According to the question,
    35 ÷ 7 x 5 + 5 - 6 = ?
    ⇒ 5 x 5 + 5 - 6 = ?
    ⇒ 25 + 5 - 6 = ?
    ⇒ 30 - 6 = 24

    Correct Option: B

    According to the question,
    35 ÷ 7 x 5 + 5 - 6 = ?
    ⇒ 5 x 5 + 5 - 6 = ?
    ⇒ 25 + 5 - 6 = ?
    ⇒ 30 - 6 = 24


Direction: In each of the following questions, all the equations except one have been solved according to a certain rule. You are required to solve the unsolved equation following the same rule and to choose the correct answer out of the given options.

  1. 4 - 4 = 12, 6 - 6 = 30, 2 - 2 = 2, 8 - 8 = ?
    1. 8
    2. 38
    3. 56
    4. 16

  1. View Hint View Answer Discuss in Forum

    As, 4 - 4 ⇒ 4 x 4 - 4 = 12
    6 - 6 ⇒ 6 x 6 - 6 = 30
    2 - 2 ⇒ 2 x 2 - 2 = 2

    Correct Option: C

    As, 4 - 4 ⇒ 4 x 4 - 4 = 12
    6 - 6 ⇒ 6 x 6 - 6 = 30
    2 - 2 ⇒ 2 x 2 - 2 = 2
    Similarly, 8 - 8 ⇒ 8 x 8 - 8 = 56



  1. 9 * 7 = 32, 13 * 7 = 120, 17 * 9 = 208, 19 * 11 = ?
    1. 64
    2. 160
    3. 240
    4. 210

  1. View Hint View Answer Discuss in Forum

    As, 9 * 7 ⇒ (9 + 7) (9 - 7) = 16 x2 = 32
    13 * 7 ⇒ (13 + 7) (13 - 7) = 20 x 6 = 120
    17 * 9 ⇒ (17 + 9) (17 - 9) = 26 x 8 = 208

    Correct Option: C

    As, 9 * 7 ⇒ (9 + 7) (9 - 7) = 16 x2 = 32
    13 * 7 ⇒ (13 + 7) (13 - 7) = 20 x 6 = 120
    17 * 9 ⇒ (17 + 9) (17 - 9) = 26 x 8 = 208
    Similarly, 19 * 11 ⇒ (19 + 11) (19 - 11) = 30 x 8 = 240
    ∴ ? = 240