1. (2024·泰兴期中)计算$(-2)^{2}×(-4)$的正确结果是(
A.16
B.-8
C.-16
D.8
C
)A.16
B.-8
C.-16
D.8
答案:C
解析:
$(-2)^{2}×(-4)=4×(-4)=-16$
C
C
2. 计算:$3×(-1)+|-3|= $
0
.答案:0
解析:
$3×(-1)+\vert-3\vert$
$=-3 + 3$
$=0$
$=-3 + 3$
$=0$
3. 计算:$-1^{2}+|-2025|= $
2024
.答案:2024
解析:
$-1^{2}+\vert-2025\vert=-1+2025=2024$
4. (2024·姜堰学校三校联考)用简便方法计算:$(-2)^{4}-\frac {13}{17}×19-\frac {13}{17}×15= $
-10
.答案:-10
解析:
$(-2)^4 - \frac{13}{17} × 19 - \frac{13}{17} × 15$
$=16 - \frac{13}{17} × (19 + 15)$
$=16 - \frac{13}{17} × 34$
$=16 - 26$
$=-10$
$=16 - \frac{13}{17} × (19 + 15)$
$=16 - \frac{13}{17} × 34$
$=16 - 26$
$=-10$
5. 计算:(1)$|-3|+(-1)^{2}=$
(3)$-3^{2}÷3×\frac {1}{3}=$
4
;(2)$12-7×(-4)+8÷(-2)=$36
;(3)$-3^{2}÷3×\frac {1}{3}=$
-1
;(4)$(-1.23)^{3}÷\frac {1}{5}×0-\frac {1}{4}=$$-\frac{1}{4}$
.答案:
(1)4
(2)36
(3)-1
(4)$-\frac{1}{4}$
(1)4
(2)36
(3)-1
(4)$-\frac{1}{4}$
6. 计算:
(1)$-2^{3}÷\frac {4}{9}×(-\frac {3}{2})^{2}$;
(2)(2024·广西)$(-3)×4+(-2)^{2}$;
(3)$2-(-3)^{2}-5×(-1)^{3}$;
(4)$\frac {4}{3}×[\frac {3}{4}×(-\frac {1}{2})-3]-\frac {3}{2}-1$.
(1)$-2^{3}÷\frac {4}{9}×(-\frac {3}{2})^{2}$;
(2)(2024·广西)$(-3)×4+(-2)^{2}$;
(3)$2-(-3)^{2}-5×(-1)^{3}$;
(4)$\frac {4}{3}×[\frac {3}{4}×(-\frac {1}{2})-3]-\frac {3}{2}-1$.
答案:解:
(1)原式$=-8×\frac{9}{4}×\frac{9}{4}=-\frac{81}{2}$.
(2)原式$=-12+4=-8$.
(3)原式$=2-9-5×(-1)=2-9+5=-2$.
(4)原式$=\frac{4}{3}×\frac{3}{4}×(-\frac{1}{2})-\frac{4}{3}×3-\frac{3}{2}-1=-\frac{1}{2}-4-\frac{3}{2}-1=-7$.
(1)原式$=-8×\frac{9}{4}×\frac{9}{4}=-\frac{81}{2}$.
(2)原式$=-12+4=-8$.
(3)原式$=2-9-5×(-1)=2-9+5=-2$.
(4)原式$=\frac{4}{3}×\frac{3}{4}×(-\frac{1}{2})-\frac{4}{3}×3-\frac{3}{2}-1=-\frac{1}{2}-4-\frac{3}{2}-1=-7$.
7. 计算$\frac {1}{2}+\frac {1}{6}+\frac {1}{12}+\frac {1}{20}+\frac {1}{30}+... +\frac {1}{9900}$的值为(
A.$\frac {1}{100}$
B.$\frac {99}{100}$
C.$\frac {1}{99}$
D.$\frac {100}{99}$
B
)A.$\frac {1}{100}$
B.$\frac {99}{100}$
C.$\frac {1}{99}$
D.$\frac {100}{99}$
答案:B
解析:
$\begin{aligned}&\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\cdots+\frac{1}{9900}\\=&\frac{1}{1×2}+\frac{1}{2×3}+\frac{1}{3×4}+\frac{1}{4×5}+\frac{1}{5×6}+\cdots+\frac{1}{99×100}\\=&\left(1 - \frac{1}{2}\right) + \left(\frac{1}{2} - \frac{1}{3}\right) + \left(\frac{1}{3} - \frac{1}{4}\right) + \left(\frac{1}{4} - \frac{1}{5}\right) + \cdots + \left(\frac{1}{99} - \frac{1}{100}\right)\\=&1 - \frac{1}{100}\\=&\frac{99}{100}\end{aligned}$
B
B
8. 计算$-4^{2}×2025+(-8)÷\frac {1}{6}×2025-2025×6^{2}$的结果为(
A.4050
B.-4050
C.202500
D.-202500
D
)A.4050
B.-4050
C.202500
D.-202500
答案:D
解析:
$-4^{2}×2025+(-8)÷\frac {1}{6}×2025-2025×6^{2}$
$=-16×2025+(-8)×6×2025-2025×36$
$=2025×(-16-48-36)$
$=2025×(-100)$
$=-202500$
D
$=-16×2025+(-8)×6×2025-2025×36$
$=2025×(-16-48-36)$
$=2025×(-100)$
$=-202500$
D
9. (2024·武威)定义一种新运算$*$,规定运算法则为$m*n= m^{n}-mn$(m,n均为整数,且$m≠0$).例:$2*3= 2^{3}-2×3= 2$,则$(-2)*2= $
8
.答案:8
解析:
$(-2)*2=(-2)^{2}-(-2)×2=4+4=8$