有几道计算题要简算2002/200220022003 893536*78 24*1953+19*2953

2002/200220022003
=2002/(200220022002+1)
=1/((200220022002+1)/2002)
=1/(100010001+1/2002)
=9.999*10^(-9)
893536*78
=893536*(100-22)
=89353600-893536*22
=69695808
24*1953+19*2953
=24*1953+19*(1953+1000)
=(24+19)*1953+19000
=43*1953+19000
=102979