An Online Teaching Video Evaluation Scheme Based on EEG Signals and Machine Learning

Table 3

The difficulty values of algebraic problems.

Type of question	Difficulty value	Type of question	Difficulty value
2-digit ± 2-digit	2	2-digit × 2-digit	8
3-digit ± 3-digit	3	3-digit × 3-digit	21
4-digit ± 4-digit	4