19+199+1999+19999 =20-1+200-1+2000-1+20000-1=22220-4=22216
(124-25)*12/26=99*12/26=(100-1)*6/13=(600-6)/13=594/13
(124-25)*12/26 19+199+1999+19999 怎么简便计算,
19+199+1999+19999 =20-1+200-1+2000-1+20000-1=22220-4=22216
(124-25)*12/26=99*12/26=(100-1)*6/13=(600-6)/13=594/13