Question

直接寫出得數(shù)． 1÷ 4 9 =	4.2×0.5=	6.4-3.25=	9.3÷0.03=	0.22=
2 3 + 1 4 =	2- 3 5 =	3 4 × 5 9 =	44÷ 11 10 =	1 3 ÷2÷ 1 3 =

Answer 1

分析：①⑨處以一個數(shù)等于乘這個數(shù)的倒數(shù)；②先算42×5，然后在結(jié)果中從后向前數(shù)出兩位，點上小數(shù)點即可；③注意小數(shù)點對齊；④把被除數(shù)與除數(shù)分別擴大100倍，再相除；⑤原式即為0.2×0.2；⑥通分計算；⑦把2化成分母為5的份數(shù)，再計算；⑧約分計算；⑩把除法改為乘法，約分即可．

解答：解：1÷

4

9

=

9

4

；    4.2×0.5=2.1；       6.4-3.25=3.15；       9.3÷0.03=310；      0.2²=0.04；

2

3

+

1

4

=

11

12

；       2-

3

5

=1

2

5

；          

3

4

×

5

9

=

5

12

；           44÷

11

10

=40；         

1

3

÷2÷

1

3

=

1

2

；

點評：掌握分數(shù)加減法、乘除法以及小數(shù)的運算法則是解答此題的關(guān)鍵．