a+1a-1a:1a10
a=1000=1000+(1*1000)-(1*1000):(1*1000)*10=19990
a=1000000=1000000+(1*1000000)-(1*1000000):(1*1000000)*10=19999990
a+1a-1a:1a10
a=1000=1000+(1*1000)-(1*1000):(1*1000)*10=19990
a=1000000=1000000+(1*1000000)-(1*1000000):(1*1000000)*10=19999990