1)395-283+154+246-117
=395+(154+246)-(283+117)
=395+400-400
=395;
(2)8795-4998+2994-3002-2008
=8795+2994-(4998+3002)-2008
=11789-8000-2008
=1781;
(3)1999+999×999
=1999+999×(1000-1)
=1999+999000-999
=1000+999000
=1000000;
(4)38×25×6
=38×(25×6)
=38×150
=5700;
故答案为395;1781;1000000;5700.