999900000000×99991×···×99991(22个99991)
=9.999×10^11×(10^6-9)^22
这道题应这样列式,即999900000000×(99991×22)=2.1995820198E18即可
9999*100000000*22*99991=(10000-1)*99991*22*100000000=(10000-1)*(100000-9)*【22*100000000】=(1000000000-110000+9)*22*100000000=100000000*22*【9+10000*(10000-11)】=22*99810009*100000000=2199582019800000000
999900000000*22*(100000-9)
=999900000000*(2200000-198)
=999900000000*2199802
=2199582019800000000
999900000000×22×99991=2.1995820198×10^18