These represent classes of problems and the test checks which classes students have covered in their studies and which they slacked on.
These two are straight-forward problems, both will be allocated some basic nominal time. You either know how to solve them or you don't. Sometimes there'd be problems that are more puzzling, because they'd combine several problem classes and will take time to unfold (this is typical in math olympics). These will be allocated more time as they require thinking and searching for a solution.
I see what you mean by classes of problems. Some of the problems from the above links I know how to do (although working out might take some time and a pen and paper) and then there are some problems where I don't know where to start. I was just never taught how to think about numbers that way even though the link says those problems are for middle school children.
From the examples I guess it is the ability to intuitively manipulate fractions? Like “oh that’s kind of like .8 of this other thing so it’s close to X” ?
These two are straight-forward problems, both will be allocated some basic nominal time. You either know how to solve them or you don't. Sometimes there'd be problems that are more puzzling, because they'd combine several problem classes and will take time to unfold (this is typical in math olympics). These will be allocated more time as they require thinking and searching for a solution.