Respuestas

2013-09-02T20:52:52+02:00
1: 11/24
2: 73/20
3:131/42
4:155/171
5: 37/24
6: 16/9
2013-09-02T21:09:51+02:00
7/12 + 1/4 - 3/8  = 7/12 + 2/8 - 3/8  (1/4  = 2/8)
                       = 7/12 - 1/8
                       = [(7*8) - (12*1)] / (12*8)  operamos todo y queda
                       = [56 - 12] / 96
                      = 44/ 96    simplificamos
                      = 22 / 48
                      = 11 / 24
          
 12/5 - 3/4 + 2   = 12/5 - 3/4 + 8/4  (8/4 = 2)
                       = 12/5 + 5/4
                      = [(12*4) + (5*5)] / (5*4)
                      = [48 + 25] / 20
                       = 73 / 20 = 3 13/20

10/3+ 2/7-1/2   = 10/3 + 4/14 - 7/14 (4/14 = 2/7, 7/14 = 1/2)
                      = 10/3 - 3/14
                     = [(10*14) - (3*3)] / (3*14)
                    = [140 - 9] / 42
                     = 131 / 42
                   = 3 5/42

4/9 + 6/19 - 5/3   = 4/9 + 6/19 - 15/9  (15/9 = 5/3)
                         = 6/19 - 11/9
                         = [(6*9) - (19*11)] / (19*9)
                        = [ 54 - 209] / 171
                        = 155 / 171
  
 3/4+2/3 -5/8+ 3 1/4 = 3/4 + 2/3 - 5/8 + [(3*4)+1] / 4
                                 = 3/4 + 2/3 - 5/8 + 13/4
                                = 16/4 + 2/3 - 5/8
                              =  32/8 + 2/3 - 5/8
                             = 27/8 + 2/3
                             = [(27*3) + (8*2)] / (8*3)
                             = [81 + 16] / 24
                             = 97/24
                             = 4 1/24

4/9- 6/18 + 5/3
  = 8/18 - 6/18 + 30/18 = 38/18 - 6/18 = 32/18 = 16/9 = 1 7/9

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