understanding, comprehension / appreciation

understand, comprehend / appreciate

(informal) and

(logic) AND

question, problem on homework etc. / a question; a matter (of time etc.) / a problem (something that needs to be dealt with); a trouble / an issue; a matter

(mathematics) A procedure for generating a value from one or more other values; operation.

to calculate

impossible to understand, utterly confused

(informal) no problem

unthinkable, out of the question