Translation:The Addition is clearly very easy.
'the addition is obviously very easy' was marked as wrong. What's incorrect about using 'obviously' instead of ' clearly' here?
I think " The addition is clearly very easy" might be added as an alternative. In the previous sentences the definite article was included eg " The subtraction" etc. There is nothing in the Greek sentence which indicates that it is a generalisation.
I'm afraid that simple is a translation to απλός, and not εύκολος. We might want to keep these two seperate, to avoid further confusion.
Don't "clearly" and "obviously" have two different translations; e.g., "σαφώς" and "προφανώς"?
"Προφανώς" is defined as both "clearly" and "obviously" among others. I just checked to be sure: