分析:(1)(2)(3)(4)(5)(6)(7)(8)依據(jù)整數(shù)和小數(shù)四則運(yùn)算計(jì)算方法解答;
(9)(10)(14)(16)依據(jù)分?jǐn)?shù)加、減法計(jì)算方法先通分再解答;
(11)(12)(13)(17)(19)根據(jù)分?jǐn)?shù)乘、除法的計(jì)算法則,進(jìn)行計(jì)算,計(jì)算過程中能約分的要先約分再計(jì)算;
(15)根據(jù)0乘以或除以非0的數(shù)都得0進(jìn)行計(jì)算;
(18)根據(jù)加法交換律和結(jié)合律進(jìn)行計(jì)算;
(20)根據(jù)乘法分配律進(jìn)行計(jì)算.
解答:解:(1)20+30=50;
(2)12×3=36;
(3)3.5-0.2=3.2;
(4)33÷1.1=30;
(5)99×6=594;
(6)0.65+2.35=3;
(7)0.1×0.03=0.003;
(8)651-105=546;
(9)2-
=1
;
(10)
+
=
;
(11)1÷
=4
;
(12)
×26=12;
(13)
÷
=2;
(14)
-
=
;
(15)12÷
×0=0;
(16)2+
=2
;
(17)
×
=
;
(18)
+
+
=1
;
(19)
×
×5=
;
(20)(0.27+0.9)÷0.9=1.3.
點(diǎn)評(píng):此題考查了多方面的知識(shí):數(shù)位對(duì)齊、運(yùn)算定律、運(yùn)算技巧等,根據(jù)題目特點(diǎn),靈活解答.