(1)12.25-3.1+0.85-6.17,
=(12.25+0.85)-3.1-6.17,
=13.1-3.1-6.17,
=3.83;
(2)2.65×1.7+1.35×1.7,
=(2.65+1.35)×1.7,
=4×1.7,
=6.8;
(3)3.6÷(1.2+0.5)×5,
=3.6÷1.7×5,
=
×5,36 17
=10
; 10 17
(4)0.125×0.38×80,
=(0.125×80)×0.38,
=10×0.38,
=3.8;
(5)21.36÷0.8-12.9,
=26.7-12.9,
=13.8.