noun
supplementary teaching material; supplementary educational resources
Refers to additional materials used alongside a main textbook, such as workbooks, handouts, or digital resources.
この教科書には副教材としてワークブックが付いています。
This textbook comes with a workbook as supplementary material.
教材 is a general term for teaching materials, while 副教材 specifically refers to supplementary materials used in addition to the main textbook.
Compound of 副 (ふく, 'supplementary, auxiliary') and 教材 (きょうざい, 'teaching materials').