How do I solve 22 across in Daily Telegraph Cryptic 31242?

Question

Accepted Answer

22 across reads "Somehow reaches dim mathematician" (10 letters); the answer is ARCHIMEDES. It's an anagram clue: the answer is a rearrangement of letters supplied by the clue itself. Look for an indicator like 'mixed', 'broken', 'cooked', or 'wild', and find a phrase whose letters add up to the answer's length. The full step-by-step breakdown is on this page.

Somehow reaches dim mathematician (10)

22A — Somehow reaches dim mathematician (10) — ARCHIMEDES