7. 28·3 – 57 98 – 23·4 + 24 (49 + 28) : 7 34 + 13·5 28·2 – 13·4 (64 + 24) : 4

1. 28 * 3 - 57 = 84 - 57 = 27

      28
   ×  3
   -----
      84
   

     84
   -57
   ---
     27
   

2. 98 - 23 * 4 + 24 = 98 - 92 + 24 = 6 + 24 = 30

      23
   ×  4
   -----
      92
   

     98
   -92
   ---
      6
   

3. (49 + 28) : 7 = 77 : 7 = 11

     49
   +28
   ---
     77
   

     11
   7|77
    -7
    --
     07
    -7
    --
     0
   

4. 34 + 13 * 5 = 34 + 65 = 99

      13
   ×  5
   -----
      65
   

     34
   +65
   ---
     99
   

5. 28 * 2 - 13 * 4 = 56 - 52 = 4

      28
   ×  2
   -----
      56
   

      13
   ×  4
   -----
      52
   

     56
   -52
   ---
      4
   

6. (64 + 24) : 4 = 88 : 4 = 22

     64
   +24
   ---
     88
   

      22
   4|88
    -8
    --
     08
    -8
    --
     0
   

Ответ: 27; 30; 11; 99; 4; 22