`d,` `100 : {250 : [350 - (4 . 5^3 - 2^3 . 25)]}`

`= 100 : {250 : [350  - (4 . 125 - 8 . 25]}`

`= 100 : {250 : [350 - (500 - 200)]}`

`= 100 : {250 : [350 - 300]}`

`= 100 : {250 : 50}`

`= 100 : 5`

`= 20`

``

`g,` `6^2 . 25 + 6^2 . 75 - 200`

`= 6^2 . (25 + 75) - 200`

`= 6^2 . 100 - 200`

`= 36 . 100 - 200`

`= 3600 - 200`

`= 3400`

``

`f,` `2^{7}.15-2^{8}+2^{7}.3`

`=2^{7}.(15+3)-2^{7}.2^{1}`

`=2^{7}.(18-2)`

`=2^{7}.16`

`=2048`

``

`e,` `24 . 93 + 6 . 68 . 4 - 24.  61`

`= 24 . 93 + 24 . 68 - 24 . 61`

`= 24 . (93 + 68 - 61)`

`= 24 . 100`

`= 2400`

`@ Neil`