买2千克{#blank#}1{#/blank#}元，买2.5千克{#blank#}2{#/blank#}元，买0.8千克{#blank#}3{#/blank#}元.

0.264÷0.99{#blank#}1{#/blank#}0.264                  0.264÷1.01{#blank#}2{#/blank#}0.264

0.264÷0.99{#blank#}3{#/blank#}0.264×0.99        0.264÷101{#blank#}4{#/blank#}0.264×1.01

0.264÷0.99{#blank#}5{#/blank#}0.264÷1.01        0.264÷0.99{#blank#}6{#/blank#}0.264-0.01

3.14×0.14{#blank#}1{#/blank#}3.14              3.14÷0.41{#blank#}2{#/blank#}3.14

7.8×1.14{#blank#}3{#/blank#}7.8-1.14           7.8÷4.11{#blank#}4{#/blank#}7.8÷1.14