1) a) ( 1/5+1/4)x2/3= b) 1/5+2/5:4/5 2) a) 13/10-5/8×4/25 b) 8/9:4/3×5/8 giúp em với ạ

2 bình luận về “1) a) ( 1/5+1/4)x2/3= b) 1/5+2/5:4/5 2) a) 13/10-5/8×4/25 b) 8/9:4/3×5/8 giúp em với ạ”

1. 1.

   a) (1/5+1/4)×2/3

   = (4/20+5/20)×2/3

   = 9/20×2/3

   = (9×2)/(20×3)

   = 18/60 = 3/10

    b)1/5+2/5:4/5

   = 1/5 + 2/5×5/4

   = 1/5 + (2×5)/(5×4)

   = 1/5 + 1/2

   = 2/10 + 5/10

   =7/10

   2)

   a) 13/10-5/8×4/25

   =13/10-(5×4)/(8×25)

   =13/10-1/10

   =6/5

   b) 8/9:4/3×5/8

   =8/9×3/4×5/8

   =(8×3)/(9×4)×5/8

   =2/3×5/8

   =(2×5)/(3×8)

   =5/12

   Trả lời
2. Giải đáp:

    

   Lời giải và giải thích chi tiết:

   1)

   a)(1/5+1/4)xx2/3

   =(4/20+5/20)xx2/3

   =9/20xx2/3

   =(9xx2)/(20xx3)

   =(3xx3xx2)/(2xx10xx3)

   =3/10

   b)1/5+2/5:4/5

   =1/5+2/5 xx 5/4

   =1/5+(2xx5)/(5xx2xx2)

   =1/5+1/2

   =2/10+5/10

   =7/10

   2)

   a)13/10-5/8xx4/25

   =13/10-(5xx4)/(8xx25)

   =13/10-(5xx4)/(4xx2xx5xx5)

   =13/10-1/10

   =12/10

   =6/5

   b) 8/9:4/3xx5/8

   =8/9xx3/4xx5/8

   =(8xx3xx5)/(9xx4xx8)

   =(3xx5)/(3xx3xx4)

   =5/12

    

   Trả lời