能简算的要简算 列式计算

问题描述:

能简算的要简算 列式计算
4/5÷[5/8×(1-1/5)] 86×4/85 = 9/17×1/7+5/17÷7
2/5÷(3/4+2/5)

4/5÷[5/8×(1-1/5)] =4/5÷【5/8 ×4/5】=4/5÷1/2=8/586×4/85 ==(85+1)×4/85=4+4/85=4又4/85 9/17×1/7+5/17÷7=9/17×1/7 +5/17×1/7=(9/17 + 5/17)×1/7=14/17×1/7=2/172/5÷(...