difficult / hard, probably impossible

(arithmetic) division

(arithmetic) division

untie; unravel; undo (a fastening); unwrap / dispel (doubts); clear up (a matter)

solve (a problem); answer (a question); unravel (a riddle) / comb; untangle (hair)

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

problem; point at issue

viewing as a problem

to view as a problem

set of problems