口算.8÷5= 0.72÷0.8= 0.25÷0.5= 0.5÷4=1.25×10= 0.5÷2= 0×l0.5= 0.8×12.5=0.4×0.7= 3÷1.5= 1.6÷0.04= 0÷2.1=
99+11×19+11×80 .
123×5.67+8.77×567= .
80×16×25×125= .
(562×397)÷(281×397)= .
29×12+29×13+29×25+29×10= .