计算大比拼.(口算)24×3= 72÷4= 7×12= 90÷18=18×5= 65÷5= 16×5= 66÷33=5×13= 54÷3= 33÷3= 85÷17=
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= .