=(1/20+2/21 +2/23 +2/25+2/27+2/29+1/30)+(1/11+1/12+1/13+1/14)
=(1/20+2/25+1/30)+(2/21+2/23+2/27+2/29)+(1/11+1/12+1/13+1/14)
=(75/1500+60/1500+50/1500)+(46/483+42/483)+(58/783+54/783)+(12/132+11/132)+(14/182+13/182)
=185/1500+89/483+112/783+23/132+27/182
=不是人计算的数字!