Question

20．直接寫出得數(shù)．

3-1.08=	1÷2$\frac{1}{4}$=	4$\frac{5}{8}$+2$\frac{3}{8}$=	0.3×0.4×50=	16$\frac{1}{2}$÷2=
5-1$\frac{2}{5}$-0.6=	98.9+9.9+0.2=	3-3×$\frac{1}{4}$=	6.37+2.63=	（$\frac{2}{5}$+$\frac{1}{5}$）÷$\frac{3}{5}$=

Answer 1

分析 根據(jù)分?jǐn)?shù)和小數(shù)加減乘除法的計(jì)算方法進(jìn)行計(jì)算；
5-1$\frac{2}{5}$-0.6根據(jù)減法的性質(zhì)進(jìn)行簡算；
98.9+9.9+0.2根據(jù)加法交換律和結(jié)合律進(jìn)行簡算．

解答 解：

3-1.08=1.92	1÷2$\frac{1}{4}$=$\frac{4}{9}$	4$\frac{5}{8}$+2$\frac{3}{8}$=7	0.3×0.4×50=6	16$\frac{1}{2}$÷2=8$\frac{1}{4}$
5-1$\frac{2}{5}$-0.6=3	98.9+9.9+0.2=109	3-3×$\frac{1}{4}$=2$\frac{1}{4}$	6.37+2.63=9	（$\frac{2}{5}$+$\frac{1}{5}$）÷$\frac{3}{5}$=1

點(diǎn)評 口算時(shí)，注意運(yùn)算符號和數(shù)據(jù)，然后再進(jìn)一步計(jì)算．