①5.27-1.98-0.02
=5.27-(1.98+0.02)
=5.27-2
=3.27;
②3.2×5.7+6.8×5.7
=(3.2+6.8)×5.7
=10×5.7
=57;
③2.5×6.8×0.4
=(2.5×0.4)×6.8
=1×6.8
=6.8;
④5.6-36÷30
=5.6-1.2
=4.4;
⑤0.72+9.6÷3.2
=0.72+3
=3.72;
⑥7.75×[20÷(3.24-3.04)]
=7.75×[20÷0.2]
=7.75×100
=775.