a) 35 – 138 + 68 – 35 b) 123 – (-79) + 31 – (31+79) c) -21 . 77 + 21 . 20 – 57 . 79

0 bình luận về “a) 35 – 138 + 68 – 35 b) 123 – (-79) + 31 – (31+79) c) -21 . 77 + 21 . 20 – 57 . 79”

1. a) 35 – 138 + 68 – 35

   = (-103)+68-35

   =(-35)-35

   =-70

   b) 123 – (-79) + 31 – (31+79)

   =123 – (-79) + 31- 110

   =202+31-110

   =233-110

   =123

   c) -21 . 77 + 21 . 20 – 57 . 79

   =(-1617)+420-4503

   =(-1197)-4503

   =-5700

    

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2. a) 35-138+68-35

   =(35-138)+(68-35)

   =-103+33

   =-70

   b) 123-(-79)+31-(31+69)

   =202+31-100

   =233-100

   =133

   c) -21.77+21.20-57.70

   =(-21.77)+(21.20)-(57.70)

   =-1617+420-3990

   =-1197-3990

   =-5187

    

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