Sometimes being bored with maths questions is good, as it teaches you to find patterns, shortcuts, etc.
I remember learning column multiplication, and when the numbers had zeroes in, we were still taught to lay it out as usual, which might have mean a whole row of zeroes in the second line, for example, which then made no difference when you added up the rows at the end. And I realised that you could just skip that step, as long as you remembered to put the right number of place holder zeroes in the next line. Or when there are two digits the same in column multiplication, what it does to the number patterns, etc. Or other somewhat more insightful shortcuts, that you develop after doing dozens of problems that can seem the same. So there are some definite benefits to having to continue something that is boring.
It's also useful to be able to do something long and boring but maintain attention enough to get it perfect - often children who are mathematically capable start to lose focus after a few questions and get things wrong on exams that they could otherwise do, because they've not practiced the stamina to keep going and keep being accurate even when a bit tired.
Developing speed is excellent, as is developing a pride in a page of neatly written, mostly-all-correct answers (Depending on the child, encouraging perfection might not be helpful - I know that as an unchallenged child, I challenged myself by trying to be perfect, which then led to some very unhelpful traits developing! But aiming for perfection whilst accepting small mistakes is beneficial).
And then also getting them challenged with some puzzles and enrichment activities. And making sure that they aren't distracting others, or acting like the work is beneath them, etc., as those might also contribute to the 'effort' grade, if it actually encompasses things like attitude and behaviour as well.