2/3+(8/14+7/14)*9/25= 2/3+15/14 * 9/25 = 2/3+ 135/350 = 2/3 + 27/70 =140/210 + 81/210=221/210 = 1.05238
按顺序使劲算,没有简便算法
=2/3+15/14x9/25=2/3+27/70=47/30
=2/3+15/14 *9/25=2/3+27/70=66/35
1又210分之11