5+55+555+5555+55555和22222乘99999+99999乘33333这两道题,怎样算简便就怎样算高手教教

5+55+555+5555+55555
=5*(1+11+111+1111+11111)
=5*12345
=61725
22222*99999+99999*33333
=99999*(22222+33333)
=(100000-1)*55555
=5555500000-55555
=5555444445