(2÷3÷7+4÷6÷14+14÷21÷49)÷(4÷7÷9+8÷14÷18+28÷49÷63)要用简便做法,并且说明原因,
问题描述:
(2÷3÷7+4÷6÷14+14÷21÷49)÷(4÷7÷9+8÷14÷18+28÷49÷63)
要用简便做法,并且说明原因,
答
(2÷3÷7+4÷6÷14+14÷21÷49)÷(4÷7÷9+8÷14÷18+28÷49÷63)
=(2÷3÷7+2÷3÷7+2÷3÷7)÷(4÷7÷9+4÷7÷9+4÷7÷9)
=(3*2÷3÷7)÷(3*4÷7÷9)
=(2÷3÷7)÷(4÷7÷9)
=2÷3÷7÷4*7*9
=2÷3÷4*9
=2/3