1)12.194+6.437.2+3,369.4=12.194+12.437+12,369=12.(194+437+369)=12x1000=12000
2)1+5+9+13+........+57+61+65.2-26
3)8.9.14+6.17.12+19.4.18=72x14+72x17+19.72=72x(14+17+19)=72x50=3600
4)1+2-3-4-5+6-7-8+9+994-995-996+997+998
5)1994.19931993-1993.19941994=0