(26÷25)×(27÷17)×(9÷25)×(17÷26)＝26/25×27/17×9/25×17/26=26/25×9/25×（27/17×17/26）=26/25×9/25×27/26=26/25×27/26×9/25=27/25×9/25=243/625
