口算(1)7+5= (2)11-6= (3)11-9= (4)7+4= (5)11-2= (6)9-9= (7)5+7= (8)4+4= (9)8+0= (10)12-8= (11)6+5= (12)11-5= (13)3+8= (14)11-7= (15)8+4= (16)12-3= (17)13-10= (18)3+9= (19)5+5= (20)3+8=
直接写出得数。 6-+= 1-0.675= 1÷20%+0.36+0.4=÷=(+)×12= 1.25×0.9×80=+-+= 2.6×7.5+74×75%=×7÷×7= 199+200+201+202+203+204+205=
5x-12.5=23×(2x+7)=45 5.6-4x=3.2
(13×0.58-4.87+0.42×13- 5.13) ×4.25
999×778+333×666
-(+)