`a) (-8,43) . 2,5 . 4`
`= (-8,43) . ( 2,5 . 4)`
`= (-8.43) . 10`
`= -84,3`
``
`b) 25 3/4 : 1 1/5 - 43 3/4 : 1 1/5`
`= 25 3/4 : 6/5 - 43 3/4 : 6/5`
`= 25 3/4 . 5/6 - 43 3/4 . 5/6`
`= ( 25 3/4 - 43 3/4) . 5/6`
`= (-18) . 5/6`
`= -15`
``
`c) 3 - 13/91 - ( 4 1/5 - 3 1/7) : 1/35`
`= 3 - 13/91 - ( 21/5 - 22/7) . 35`
`= 3 - 13/91 - (147/35 - 110/35) . 35`
`= 3 - 13/91 - 37/35 . 35`
`= 3 - 13/91 - 37`
`=(3 - 37) - 13/91`
`= (-34) - 13/91`
`=-34- 1/7`
`=-238/7 - 1/7`
`= -239/7`
``
`d) (-2/5)^2 + 0,5 . ( 9/2 - 2) + ((-2)^3)/4`
`= 4/25 + 1/2 . (9/2 - 4/2) + (-8)/4`
`= 4/25 + 1/2 . 5/2 + (-2)`
`= 4/25 + 5/4 + (-2/1)`
`= 16/100 + 125/100 - 200/100`
`=-59/100`
