Ответ:

  1. 7 × □ + 55 = 111

    7 × □ = 111 − 55 = 56

    □ = 56 : 7 = 8

  2. 36 : □ + 284 = 293

    36 : □ = 293 − 284 = 9

    □ = 36 : 9 = 4

  3. 9 × □ + 797 = 878

    9 × □ = 878 − 797 = 81

    □ = 81 : 9 = 9

  4. 48 : □ + 514 = 522

    48 : □ = 522 − 514 = 8

    □ = 48 : 8 = 6

Ответ: 8; 4; 9; 6.