Hi, i assign 460 GWh to a E variable (Giga Watt hours).
Then I want to see it in kWh (or MWh).
Trying to write E='MWh results as on picture (units are not recalculated by prefixes).
Is it normal? Do I have to add my own calculation among prefixes to obtain proper recalculation?

Interesting but rather confusing.
What is MW h
In lot of maths MW h is implicit of MW*h
Rather not same MW/h

Two very different things [W*h]=[J] while [W/h]=[J/s^2]

However, yes, can be done even this (CTRL+K to add the backslash):

Hi "M". Just not so fast. J/s^2 can be seen as the power acceleration, like the normal "acceleration", meter by second square. It could be practical in an electrical circuit for study the variation of p(t)=v(t)*i(t) (in lowercase, which means instant values). Usual electrical protections only study the "R by I square curve" and how the current increase in time (and remember that i=dq/dt), but one must to remember that Ohm's law isn't a "true" law: it's just a practical rule, which works only ... if it works, but isn't a natural principle, like Newton's laws.

Best regards.

Alvaro.