Bài 1: Thực hiện phép tính sau : a) -5/9 + 7/9 b ) 1/2 + -3/4 c ) 7/13 – ( 13/15 + 7/13 ) d ) 6/11 . 10/17 . + 5/11 + 6/11

2 bình luận về “Bài 1: Thực hiện phép tính sau : a) -5/9 + 7/9 b ) 1/2 + -3/4 c ) 7/13 – ( 13/15 + 7/13 ) d ) 6/11 . 10/17 . + 5/11 + 6/11”

1. Bài 1.

   a, -5/9 + 7/9 = 2/9

   b,1/2 + (-3/4) = -1/4

   c,7/13 – (13/15 + 7/13) = 7/13-247/195=-142/195

   d ) 6/11 . 10/17 + 5/11 + 6/11 . 7/17=60/187+5/11+42/187=1

   e )-2/11 + -9/11=-1

   f ) 11/2 – (-3/4) = 6,25

   g ) 12/11 – (-7/19) + 12/19=305/209 + 12/19= 23/11

    

   Trả lời
2. Giải đáp:

   a) (-5)/9 + 7/9

   = (-5+7)/9

   = 2/9

   b) 1/2 + (-3)/4

   = 2/4 -3/4

   = (2-3)/4

   =(-1)/4

   c) 7/13 – (13/15 +7/13)

   = 7/13 – 13/15 -7/13

   = ( 7/13 – 7/13 ) -13/15

   = 0-13/15

   = 13/15

   d) 6/11 . 10/17 + 5/11+6/11 . 7/17

   = 6/11 . ( 10/17 + 7/17 ) + 5/11

   = 6/11 . 17/17 + 5/11

   = 6/11 . 1 + 5/11

   = 6/11 + 5/11

   = (6+5)/11

   = 11/11

   e) (-2)/11 + (-9)/11

   = (-2)/11 -9 /11

   = (-2-9)/11

   = (-11)/11

   =-1

   f) 11/2 – (-3)/4

   = 22/4 + 3/4

   = (22+3)/4

   =25/4

   g) 12/11 – (-7)/19 + 12/19

   = 12/11 + 7/19 + 12/19

   = 12/11 + (7/19 +12/19)

   = 12/11 + 19/19

   = 12/11 + 1

   = 12/11 + 11/11

   =23/11

   h) (-5)/7 . 2/11 +(-5)/7 . 9/11 + 5/7

   = 5/7 . (-2)/11 + 5/7 . (-9)/11 + 5/7 . 1

   = 5/7 . ( ( -2)/11 + (-9)/11 + 1)

   = 5/7 . ( -1 +1)

   = 5/7 . 0

   = 5/7

   Trả lời