Tính: a) 4/5 * 9 ; 10 : 8/9 ; 2/5 – 4 b) 5/6 + 7/8 ; 9/2 – 4/5 ; 10 – 4/5 c) 4/5 * 2/8 + 1/4 d) 10 – 2/6 : 1/2 MONG MN

0 bình luận về “Tính: a) 4/5 * 9 ; 10 : 8/9 ; 2/5 – 4 b) 5/6 + 7/8 ; 9/2 – 4/5 ; 10 – 4/5 c) 4/5 * 2/8 + 1/4 d) 10 – 2/6 : 1/2 MONG MN”

1. Đáp án:

    

   Giải thích các bước giải:

    ` 4/5 . 9 = 36/5 `

   ` 10 : 8/9 = 10 . 9/8 = 45/4 `

   ` 2/5 – 4 = -18/5 `

   `b) 5/6 + 7/8 = 40/48 + 42/48 = 82/48 = 41/24 `

   ` 9/2 – 4/5 = 9/2 + ( -4/5 ) = 45/10 + ( -8/10 ) = 37/10 `

   ` 10 – 4/5 = 10 + (-4/5 ) = 46/5 `

   `c) 4/5 . 2/8 + 1/4 = 1/5 + 1/4 = 4/20 + 5/20 = 9/20 `

   `d) 10 – 2/6 : 1/2 = 10 – 2/3 = 28/3 `

   Bình luận

2. Đáp án:

   a)` 4/5 * 9 = 4/5` x `9/1`

   `= 36/5`

   ` 10 : 8/9 = 10 `x `9/8`

   `= 5 `x `9/4`

   `= 45 /4`

   `2/5 – 4 = 2/5 – 20 /5`

   `= (2-20)/5`

   `=-18/5`

   b)` 5/6 + 7/8 = 10/12 + 21/12`

                       `= 31/12`

   `9/2 – 4/5 = 45/10 -8/10`

   `=37/10`

   `10 – 4/5 = 50/5 – 4/5 `

   `=45/5`

   c) `4/5 `x` 2/8 + 1/4`

   `= 1/5 `x `2/2 + 1/4`

   `= 1/5 `x `1 + 1/4`

   `=1/5 + 1/4`

   `= 4/20 + 5/20`

   `=9/20`

   d) `10 – 2/6 : 1/2 = 10 – 2/6 : 1/2`

   `= 10 -2/6 `x`2 `

   `= 10 -2/3 `x`1`

   `=10 – 2/3`

   `= 30/3 – 2/3`

   `= 28/3`

   mong ctlhn ạ~~~

    

   Bình luận