9×55+49 =9×（49+6）+49=9×49+9×6+49=9×49+49+54=（9+1）×49+54=490+54=544 128×8 =(125+3)×8=125×8+3×8=1000+24=1024 302×25 =（300+2）×25=300×25+2×25=7500+50=7550
数学题，9×55+49 128×8 302×25 用简便方法计算过程。谢谢解答
9×55+49 =9×（49+6）+49=9×49+9×6+49=9×49+49+54=（9+1）×49+54=490+54=544 128×8 =(125+3)×8=125×8+3×8=1000+24=1024 302×25 =（300+2）×25=300×25+2×25=7500+50=7550