Question

（2012?廣州一模）

直接寫(xiě)出得數(shù)． 3- 1 3 =	0.23+1.7=	5 6 + 1 7 =	2.375+3 5 8 =	1- 1 2 ÷ 1 2
4 5 ÷ 5 4 =	0.04×0.5=	25×3.6=	1 5 ×3÷ 1 5 ×3=	98+2×5=

Answer 1

分析：①把3化為分母為3的分?jǐn)?shù)，然后相減；②注意小數(shù)點(diǎn)對(duì)齊；③通分計(jì)算；④把分?jǐn)?shù)化為小數(shù)計(jì)算；⑤先算除法，再算減法；⑥把除法改為乘法，再計(jì)算；⑦先算4×5，然后在結(jié)果中從后向前數(shù)出三位，點(diǎn)上小數(shù)點(diǎn)；⑧把3.6看作4×0.9，運(yùn)用乘法結(jié)合律簡(jiǎn)算；⑨把除法改為乘法，約分計(jì)算；⑩先算乘法，再算加法．

解答：解：3-

1

3

=2

2

3

；     0.23+1.7=1.93；        

5

6

+

1

7

=

41

42

；       2.375+3

5

8

=6；         1-

1

2

÷

1

2

=0；

4

5

÷

5

4

=

16

25

；       0.04×0.5=0.02；        25×3.6=90；      

1

5

×3÷

1

5

×3=9；      98+2×5=108．

點(diǎn)評(píng)：此題考查了小數(shù)、分?jǐn)?shù)的運(yùn)算，根據(jù)題目特點(diǎn)，采取靈活的方法解答．