简便运算2÷（二又九分之二×五分之四+二又九分之二×6.2—5.8×二又九分之二—五分之一×二又九分之二）

原式=2÷［2又9分之2 ×(4/5+6.2-5.8-1/5)］×9/20
=2÷［2又9分之2×(3/5+0.4)］×9/20
=2÷［2又9分之2×(0.6+0.4)］×9/20
=2÷(2又9分之2×1)×9/20
=2÷(2又9分之2)×9/20
=2÷(20/9)×9/20
=2×9/20×9/20
=81/200