题目内容
耐心算一算:
①24+(-14)+(-16)+8:
②(+
)-(-
)-|-3|
③-7
×62
④(
-
+
)×(-36)
⑤-54×2
÷(-4
)×
⑥-5×(-3
)+(-9)×(+3
)+17×(-3
)
⑦9-23÷(-4)×(-7+5)
⑧-14-[1-(1-0.5×
)]×6.
①24+(-14)+(-16)+8:
②(+
| 3 |
| 4 |
| 5 |
| 4 |
③-7
| 30 |
| 31 |
④(
| 1 |
| 2 |
| 5 |
| 9 |
| 7 |
| 12 |
⑤-54×2
| 1 |
| 4 |
| 1 |
| 2 |
| 2 |
| 9 |
⑥-5×(-3
| 4 |
| 7 |
| 4 |
| 7 |
| 4 |
| 7 |
⑦9-23÷(-4)×(-7+5)
⑧-14-[1-(1-0.5×
| 1 |
| 3 |
分析:①先化简,再计算即可;
②从左往右依次计算;
③④⑥根据乘法分配律计算;
⑤将除法变为乘法,再约分计算即可;
⑦⑧按照有理数混合运算的顺序,先乘方后乘除最后算加减,有括号的先算括号里面的.
②从左往右依次计算;
③④⑥根据乘法分配律计算;
⑤将除法变为乘法,再约分计算即可;
⑦⑧按照有理数混合运算的顺序,先乘方后乘除最后算加减,有括号的先算括号里面的.
解答:解:①24+(-14)+(-16)+8
=24-14-16+8
=32-30
=2;
②(+
)-(-
)-|-3|
=2-3
=-1;
③-7
×62
=(-8+
)×62
=-8×62+
×62
=-496+2
=-494;
④(
-
+
)×(-36)
=-
×36+
×36-
×36
=-18+20-21
=-19;
⑤-54×2
÷(-4
)×
=-54×
×(-
)×
=6;
⑥-5×(-3
)+(-9)×(+3
)+17×(-3
)
=(5-9-17)×
=-21×
=-75;
⑦9-23÷(-4)×(-7+5)
=9-8÷(-4)×(-2)
=9-4
=5;
⑧-14-[1-(1-0.5×
)]×6
=-1-[1-(1-
)]×6
=-1-
×6
=-1-1
=2.
=24-14-16+8
=32-30
=2;
②(+
| 3 |
| 4 |
| 5 |
| 4 |
=2-3
=-1;
③-7
| 30 |
| 31 |
=(-8+
| 1 |
| 31 |
=-8×62+
| 1 |
| 31 |
=-496+2
=-494;
④(
| 1 |
| 2 |
| 5 |
| 9 |
| 7 |
| 12 |
=-
| 1 |
| 2 |
| 5 |
| 9 |
| 7 |
| 12 |
=-18+20-21
=-19;
⑤-54×2
| 1 |
| 4 |
| 1 |
| 2 |
| 2 |
| 9 |
=-54×
| 9 |
| 4 |
| 2 |
| 9 |
| 2 |
| 9 |
=6;
⑥-5×(-3
| 4 |
| 7 |
| 4 |
| 7 |
| 4 |
| 7 |
=(5-9-17)×
| 25 |
| 7 |
=-21×
| 25 |
| 7 |
=-75;
⑦9-23÷(-4)×(-7+5)
=9-8÷(-4)×(-2)
=9-4
=5;
⑧-14-[1-(1-0.5×
| 1 |
| 3 |
=-1-[1-(1-
| 1 |
| 6 |
=-1-
| 1 |
| 6 |
=-1-1
=2.
点评:本题考查的是有理数的运算能力.注意:
(1)要正确掌握运算顺序,在混合运算中要特别注意运算顺序:先三级,后二级,再一级;有括号的先算括号里面的;同级运算按从左到右的顺序;
(2)去括号法则:--得+,-+得-,++得+,+-得-.
(1)要正确掌握运算顺序,在混合运算中要特别注意运算顺序:先三级,后二级,再一级;有括号的先算括号里面的;同级运算按从左到右的顺序;
(2)去括号法则:--得+,-+得-,++得+,+-得-.
练习册系列答案
相关题目