Wrong result

[Pantasilea]

Expression: 1 - (e ^ (-200000 / 300000))
Correct answer: 0.486582881
Microsoft's calculator answer: 0.5134171190325920268719864261266

You must press the "=" button to get the correct result and this is an issue because the user expects the correct answer of the entire expression the moment all parenthesis are closed.

[Pantasilea]

Something simple like 1 - (1.5 / 4.2) also gives the wrong result.