800-250= | 30×40= | 8100÷900= | 10-0.98= | 105÷7= | 560+770= | ||||||||||||
0.25×0.4= | 6.3÷0.07= | 0.64÷8= | 8.85×10= | 4.73+0.7= |
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|
|
|
3.6×
|
8×1.36×1.25= | 7.2×2.8+2.8×0.8= |
分析:8×1.36×1.25运用乘法交换律简算;7.2×2.8+2.8×0.8运用乘法分配律简算;其它题目根据运算法则直接求解.解答:解:
800-250=550,
30×40=1200,
8100÷900=9,
10-0.98=9.02,
105÷7=15,
560+770=1330,
0.25×0.4=0.1,
6.3÷0.07=90,
0.64÷8=0.08,
8.85×10=88.5,
4.73+0.7=5.43,
3
9
+
7
9
=
10
9
,
5
8
×
4
10
=
1
4
,
5
6
÷3=
5
18
,
5
8
-
1
2
=
1
8
,
3.6×
1
4
=0.9,
8×1.36×1.25=13.6,
7.2×2.8+2.8×0.8=22.4.
点评:口算题目要求快速准确,能运用简算方法的要简算.