a, 16.38+38.84
=38.(16+84)
=38.100
=3800
b, (25+108)-(46+25+108)
=25+108-46-25-108
=(25-25)+(108-108)-46
=-46
c, 3^2.(-76)+24.(-9)+100
=3^2.(-76)+24.(-9)+100
= 9 .(-76)+24.(-9)+100
= 9 . ( -76 - 24) + 100
= 9 . ( -100) + 100
= -900 + 100
= -800
d, (-12).72+12.(-28)-200
= 12. ( -72 - 28 ) - 200
= 12 . ( -100) - 200
= -1200 - 200
= -1400