9+3分之2+99+3分之2+999+3分之2+1
=9+2/3+99+2/3+999+2/3+1
=9+2/3+99+2/3+999+2/3+3/3
=9+2/3+1/3+99+2/3+1/3+999+2/3+1/3
=9+1+99+1+999+1
=1000+100+10
=1110
就是把后面的1拆成三个三分之一
9+2/3+99+2/3+999+2/3+1 用加法分配律解
=9+99+999+【2/3+2/3+2/3+1】
=9+99+999+1+1+1
=【1+9】+【99+1】+【999+1】
=1110
9+2/3+99+2/3+999+2/3+1
=9+99+999+3×2/3+1
=9+99+999+3
=(9+1)+(99+1)+(999+1)
=10+100+1000
=1110