An abstract representational system studying numbers, shapes, structures, quantitative change and relationships between them.
A person's ability to count, calculate, and use different systems of mathematics at differing levels.
A difficulty that has to be resolved or dealt with.
A puzzling circumstance.
A set of moves required to complete a climb.
A question to be answered, schoolwork exercise.
Objection.
Difficulty in accepting or understanding or refusal to accept or understand.
Causing a problem; problematic; troublesome.
Difficult to train or guide; unruly.