课题:1.5同底数幂的除法更多资源xiti123.taobao.com在上节课我们计算过地球和太阳的体积,如果地球的体积大约是太阳的体积大约为。请问太阳的体积是地球体积的多少倍?3111005.9千米3171005.9千米611611111711171010101010101005.91005.9(1)610610111010111711171010101010101010101010101005.91005.9)2(个个个试一试:计算(1)(2)(a≠0)(3)(4)47101035aanm33qp)2()2(同底数幂除法的运算性质:(a≠o,m,n都为正整数,且m﹥n)nmanmanamnmaaaaaaaaaaaa个个个)(练一练:例1、计算47)1(aa36)())(2(xx36))(3(xx)())(4(4xyxy122)5(mmbb35)())(6(mnnm想一想:1000=10(3)8=2(3)100=10(2)4=2(2)10=10(1)2=2(1)1=10(0)1=2(0)猜一猜:0.1=10(-1)=2(-1)0.01=10(-2)=2(-2)0.001=10(-3)=2(-3)214181例2用小数或分数表示下列各数:310)1(2087)2(4106.1)3(解:001.01000110110)1(336418118187)2(222000016.00001.06.11016.1106.1)3(44三、过手训练:1、判断正误,并改正,,得2=323636)1(aaaa1)1)(2(012)3(01302、计算:(n为正整数)3、(1)(2)=1,则x=;若则,58))(1(mm)())(2(7xyyx2332)3(mmaa1232)()()4(nnyxyxm,xxxm则若5212123x,313x1x320)21()31()2004()3(:计算的值求已知yxyxba:25,5,5)4(更多资源xiti123.taobao.com四、课时小结:1.同底数幂的除法运算法则,底数不变,指数相减。2.都为整数,“m>n”的条件可以取消;3.当m=n时,(a≠0)4.当m<n时nmaaanmnm.,10aaaanmnm)为正整数p(aa1aaaapmnm)(nnmnm