①9.9÷2.2+3.7×9.9
=4.5+36.63
=41.13
②10.92÷0.52-7.5×0.42
=21-3.15
=17.85
③8.8÷1.1+3.9÷1.3
=8+3
=11
④12.56×0.8-9.75÷3
=10.048-3.25
=6.798
祝你成功 耶