Bài 1:Tính hợp lý. a) -(81–32–47)+(81–32–2) b)50–(47+50–18)+(47–18) c) 13–15+49–13+15–48 d) -(15–47+58)+(15–47)+3 *Mong giúp đỡ^^

0 bình luận về “Bài 1:Tính hợp lý. a) -(81–32–47)+(81–32–2) b)50–(47+50–18)+(47–18) c) 13–15+49–13+15–48 d) -(15–47+58)+(15–47)+3 *Mong giúp đỡ^^”

1. Đáp án:

    

   Giải thích các bước giải:

   `a,-(81-32-47)+(81-32-2)`

   `=-81+32+47+81-32-2`

   `=(-81+81)+(32-32)+47-2`

   `=45`

   `b,50-(47+50-18)+(47-18)`

   `=50-47-50+18+47-18`

   `=(50-50)+(-47+47)+(18-18)`

   `=0`

   `c,13-15+49-13+15-48`

   `=(13-13)+(-15+15)+(49-48)`

   `=1`

   `d,-(15-47+58)+(15-47)+3`

   `=-15+47-58+15-47+3`

   `=(-15+15)+(47-47)-58+3`

   `=-55`

   Bình luận

2. `\text{Bài 1:}`

   `a) -(81-32-47)+(81-32-2)`

   `= -81+32+47+81-32-2`

   `=-81+32+47+81+(-32)+(-2)`

   `=[(-81)+81]+[32+(-32)]+[47+(-2)]`

   `=0+0+45`

   `=45`

   `b) 50-(47+50-18)+(47-18)`

   `=50-47-50+18+47-18`

   `=50+(-47)+(-50)+18+47+(-18)`

   `=[50+(-50)]+[(-47)+47]+[18+(-18)]`

   `=0+0+0=0`

   `c) 13-15+49-13+15 -48`

   `=13+(-15)+49+(-13)+15+(-48)`

   `=[13+(-13)]+[(-15)+15]+[49+(-48)]`

   `=0+0+1=1`

   `d) -(15–47+58)+(15–47)+3`

   `= -15+47-58+15-47+3`

   `= -15+47+(-58)+15+(-47)+3`

   `=[15+(-15)]+[47+(-47)]+[(-58)+3`

   `=0+0+(-55)`

   `=-55`

   Bình luận