1.按不开票卖，赚50-45.33/1.13=9.88，进项留抵扣=45.33/1.13*0.13=5.21 按开票卖，赚56.5/1.13-45.33/1.13=9.88，缴纳增值税=56.5/1.13*13%-5.21=1.29。合计赚9.88-1.29=8.59 2.卖5000不开票，赚8023-5000=3023，缴纳税额1042，合计赚3023-1042=1981