(1/3÷7/9-3/10)÷1-1/2*□)要使算式结果为1,□里应填

题目

(1/3÷7/9-3/10)÷1-1/2*□)要使算式结果为1,□里应填

答案

1-1/2*□=9/70
(1/3÷7/9-3/10)÷(1-1/2*□)=1
1-1/2*□=1/3÷7/9-3/10
1-1/2*□=1/3×9/7-3/10
1-1/2*□=3/7-3/10
1-1/2*□=9/70
2-□=9/35
□=2-9/35
□=61/35