口算.5+4= 5-3= 3+0=8+7= 9+7= 7-7=3+5= 10-4= 9-8=7-2= 7-6= 3+7=10-6= 9-6= 9-5=5-4= 8-3= 5+2=
45÷×-1
×14
×9+12×
(2.5-2.5× 0.6)÷0.4
0.5÷[一(一)]