tính bằng cách thuận tiện a) 47/53 (17/3-53/47)+17/3 (6/17-47/53) b) -41/32 (15/8-16/41)+ 15/8(41/32-8/3)

`a,` `47/53.(17/3-53/47)+17/3.(6/17-47/53)`

`=47/53. 17/3-47/53. 53/47+17/3. 6/17-17/3. 47/53 `

`=(47/53. 17/3-17/3. 47/53)-47/53. 53/47+17/3. 6/17 `

`=0-1+2`

`=1`

`b,` `{-41}/32.(15/8-16/41)+15/8.(41/32-8/3)`

`=-41/32. 15/8+41/32. 16/41+15/8. 41/32-15/8. 8/3`

`=(15/8. 41/32-41/32. 15/8)+41/32. 16/41-15/8. 8/3`

`=0+1/2-5`

`={1-10}/2`

`={-9}/2`