What does the cryptic crossword clue "Multiplication aid ignored by son in a series of lessons (9)" mean?

The wordplay uses a deletion. TIME (synonym="TIME") + TABLE (synonym="‘multiplication aid’") = TIMETABLE The answer is TIMETABLE.

Multiplication aid ignored by son in a series of lessons (9)

Guardian Cryptic #29498 | 17 Across | 2024-09-26 flower