Translation:The calculation is made more quickly by a computer.
ilona50, the problem with your answer is the word "much". The French "plus" does not mean "much". Rather, the phrase "plus rapidement" means simply "faster/more rapidly (comparative), not "much faster".
In other words, you can say "faster" instead of "more quickly", but you cannot say "much faster" unless you mean "much more quickly".
"The calculation is done more quickly with a computer" should be accepted as an English translation, but it is not.
Additionally, "... by computer" should be accepted but is not, where "by computer" is used analogously to "by hand." See for example the headline here: https://www.theregister.co.uk/2017/02/08/ministry_justice_conviction_by_computer_scheme_go_ahead/
Thanks for clarifying. I opened the discussion to see if anyone had commented on DL's choice of made rather than done. I am a native AE speaker, and I would use done, as boydell did here, without a doubt. I do see however that a comment was made above by an Australian teacher, saying he would use "made."
In English one can refer to the general concept of calculation by using either the singular or the plural. In other words, one can say either "Calculation is made easier by a computer" or "Calculations are made easier by a computer."
But what about the French? Ginkkou, you seem to be saying for the general sense, only the plural "Les calculs" can be used, not the singular "Le calcul". You therefore conclude that "Le calcul est" can only be translated as "The calculation is" and not as the general "Calculation is".
But is that really so? Can't the French say "that will require some calculation" (the act of calculating) as well as "that will require some calculations" (specific acts of calculation)?
The two possibilities are "more quickly made" and "quickly made". (Any correct solution must include "made"). Of those two, only "more quickly made" is correct here.
For "quickly made", the French would be "est fait rapidement" rather than "est fait plus rapidement". (It is the French word "plus" that means "more" here.)
Informally, some English speakers might say "quicker" rather than "more quickly". Strictly speaking, "quicker" is not correct here, but at least it captures the comparative aspect, which "quickly" by itself does not.