实验小学要为四、五年级的同学每人买一本价格是15元的作文辅导书.已知四年级有123人,五年级有128人,两个年级一共需要多少元?
9-4= 8-2= 9-7= 4-4= 10-5= 4-2=
8-5= 10-3= 9-3= 10-7= 7-5= 6-4=
7-4= 6-0= 5-2= 10-9= 10-8= 8-2=
5-3= 7-2= 9-1= 7-1= 8-5= 6-3=
6-5= 7-4= 7-6 = 10-8= 10-3= 5-3=