a)756+442-56-142
=(756-56)+(442-142)
=700+300
=1000.
b)2009^0+[5^13:5^11+(135+130)^3]
=2009^0+(5^13:5^11+265^3)
=2009^0+(5^2+265^3)
=2009^0+(25+18609625)
=2009^0+18609650
=1+18609650
=18609651
c)(2+2^3+2^5+...+2^99).(51.120-60.102)
=(2+2^3+2^5+..+2^99).(6120-6120)
=(2+2^3+2^5+...+2^99).0
=0