`A)` `4.` `5^2` `-` `2.` `3^2`
`=` `2^2` . `5^2` `-` `2` . `3^2`
`=` `(2.5)^2` `-` `2.9`
`=` `10^2` `-` `18`
`=` `100-18`
`=` `82`
`B)` `76-[26+(16-2.7)^3]`
`=` `76-[26+2^3]`
`=` `76-[26+8]`
`=` `76-34`
`=` `42`
`C)` `18.151-51.18`
`=18.(151-51)`
`=18.100`
`=1800`