题目内容
用简便方法计算:
(1)[2
+(5.4-3
)×1
]÷3
(2)
×(4.85÷
-3.6+6.15×3
)
(3)
×[(3-1
)÷1
]
(4)
×5
+5
+5
÷2
.
(1)[2
1 |
3 |
2 |
3 |
2 |
3 |
4 |
9 |
(2)
1 |
4 |
5 |
18 |
3 |
5 |
(3)
2 |
9 |
3 |
5 |
1 |
3 |
(4)
4 |
7 |
1 |
3 |
1 |
3 |
1 |
3 |
1 |
3 |
考点:分数的简便计算
专题:运算定律及简算
分析:(1)中括号里面根据乘法分配律进行简算,再算加法,最后算除法;
(2)根据乘法分配律和乘法交换律进行简算;
(3)先算减法,再算除法,最后算乘法;
(4)根据乘法分配律进行简算.
(2)根据乘法分配律和乘法交换律进行简算;
(3)先算减法,再算除法,最后算乘法;
(4)根据乘法分配律进行简算.
解答:
解:(1)[2
+(5.4-3
)×1
]÷3
=[2
+(5.4×1
-3
×1
)]÷3
=[2
+(9-6
)]÷3
=[2
+2
]÷3
=5
÷3
=
;
(2)
×(4.85÷
-3.6+6.15×3
)
=
×(4.85×3.6-3.6+6.15×3.6)
=
×(4.85-1+6.15)×3.6
=
×10×3.6
=
×3.6×10
=0.9×10
=9;
(3)
×[(3-1
)÷1
]
=
×[1
÷1
]
=
×
=
;
(4)
×5
+5
+5
÷2
=
×5
+5
+5
×
=(
+1+
)×5
=2×5
=10
.
1 |
3 |
2 |
3 |
2 |
3 |
4 |
9 |
=[2
1 |
3 |
2 |
3 |
2 |
3 |
2 |
3 |
4 |
9 |
=[2
1 |
3 |
1 |
9 |
4 |
9 |
=[2
1 |
3 |
8 |
9 |
4 |
9 |
=5
2 |
9 |
4 |
9 |
=
47 |
31 |
(2)
1 |
4 |
5 |
18 |
3 |
5 |
=
1 |
4 |
=
1 |
4 |
=
1 |
4 |
=
1 |
4 |
=0.9×10
=9;
(3)
2 |
9 |
3 |
5 |
1 |
3 |
=
2 |
9 |
2 |
5 |
1 |
3 |
=
2 |
9 |
21 |
20 |
=
7 |
30 |
(4)
4 |
7 |
1 |
3 |
1 |
3 |
1 |
3 |
1 |
3 |
=
4 |
7 |
1 |
3 |
1 |
3 |
1 |
3 |
3 |
7 |
=(
4 |
7 |
3 |
7 |
1 |
3 |
=2×5
1 |
3 |
=10
2 |
3 |
点评:此题主要考查分数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
练习册系列答案
相关题目