7.8÷0.1○7.8    3.5×7.28○7.28    2.7○2.7÷0.8    15×0.6○15×1
3.6÷1.2○3.6    0.82×0.99○0.82    3.57÷1.05○3.57    5.85÷0.9○5.85
2.75×1.01○2.75    4.95÷0.9○4.95    1×1.009○1.009    3.6×1.45○3.6．