Ответ:\(900:100=9\);\(81:9:9\cdot1-1=1-1=0\);\(81:81+64\cdot0=1+0=1\);\(510:3+1\cdot58=170+58=228\);\(300:10=30\);\(23\cdot10=230\);\(28:(5-21:21)=28:(5-1)=28:4=7\);\(300:30=10\);\(400:4=100\).