1. Bỏ dấu ngoặc rồi tính a, 14 – 23 + ( 5 – 14) – (5 – 23) + 17 b, (15 – 14 + 23 – 6 ) – 3 – ( 15 – 14 – 6 ) c, 22 – ( 4 – 8

2 bình luận về “1. Bỏ dấu ngoặc rồi tính a, 14 – 23 + ( 5 – 14) – (5 – 23) + 17 b, (15 – 14 + 23 – 6 ) – 3 – ( 15 – 14 – 6 ) c, 22 – ( 4 – 8”

1. Giải đáp:

   a) 14 – 23 + ( 5 – 14) – (5 – 23) + 17                         b) (15 – 14 + 23 – 6 ) – 3 – ( 15 – 14 – 6 )

   =14-23+5-14-5+23+17                                         =15-14+23-6-3-15+14+6

   =(14-14)+(23-23)+(5-5)+17                                   =(15-15)+(14-14)+(6-6)+(23-3)

   =0+0+0+17                                                            =0+0+0+20  

   =17                                                                          =20

   c, 22 – ( 4 – 8 + 12 ) + ( 8- 12 + 4)                           d, 20 – ( 25 – 98 + 72 ) + ( 25 – 98 +  72 )

   =22-4+8-12+8-12+4                                              =20-25+98-72+25-98+72

   =22+(4-4)+(8-8)+(12-12)                                        =20+(25-25)+(98-98)+(72-72)

   =22+0+0+0                                                             =20+0+0+0

   =22                                                                           =20

    

   Trả lời
2. Lời giải và giải thích chi tiết:

   a) 14 -23 + (5-14)-(5-23)+17

   = 14 – 23 + 5-14 -5 +13 +17

   = (14-14)  + (-23 +23 ) +(5 -5 )+17

   = 0+17

   =17

   b) (15 – 14 +23 -6) -3-(15 -14 -6)

   = 15 – 14 +23 – 6 -3 -15 +14 +6

   = (15-15)+(-14+14 ) +(23 -3 )+(-6+6)

   = 20

   c)22 -(4 – 8 +12 ) +(8 – 12 + 4)

   = 22-4+8-12 + 8 -12 +4

   =(22 -12) + (-4+4) +( 8+8-12)

   = 10 + 4

   =14

   d) 20 – (25 – 98 +72 )+(25 – 98 +72)

   = 20 – 25 +98 -72 + 25 – 98 +72

   = 20 – ( 25 -25) + ( 98-98) -(72-72)

   = 20 – 0

   = 20

   Trả lời