8Mayer R E. Educational Psychology: A cognitive approach [M]. Little Brown, 1987. 88.
9Lewis A B. Training students to representation arithmetic word problem [J]. Journal of Educational Psychology, 1989,81(4): 521-531.
10Conney J B. Individual differences in memory for mathematical story problems: memory span and problem perception [J]. Journal of Educational Psychology, 1990, 82(3):570-577.