Question

直接寫出得數(shù)．

0.5÷0.01=	3 4 ×2.8=	2- 7 5 =	2.5×12=
0.8-0.36=	2.3÷10%=	5 8 × 4 15 =	800-498=

Answer 1

分析：①把被除數(shù)和除數(shù)分別擴(kuò)大100倍即可；②4與2.8約分計(jì)算；③把分?jǐn)?shù)化為小數(shù)計(jì)算；④把12看作4×3，運(yùn)用乘法結(jié)合律簡算；⑤小數(shù)點(diǎn)對齊；⑥把百分?jǐn)?shù)化為小數(shù)，再計(jì)算；⑦約分計(jì)算；⑧把498看作500-2，運(yùn)用加法結(jié)合律簡算．

解答：解：①0.5÷0.01=50；            ②

3

4

×2.8=2.1；             ③2-

7

5

=0.6；           ④2.5×12=30；
⑤0.8-0.36=0.44；               ⑥2.3÷10%=23；             ⑦

5

8

×

4

15

=

1

6

；         ⑧800-498=302．

點(diǎn)評：此題考查了多方面的知識，根據(jù)題目特點(diǎn)，靈活解答．