1.(2024·天津)计算$3-(-3)$的结果等于(
A.-6
B.0
C.3
D.6
D
)A.-6
B.0
C.3
D.6
答案：D
解析：
$3 - (-3) = 3 + 3 = 6$，答案选D。
2.(2024·杭州模拟)$|-3|-(-2)=$(
A.-1
B.5
C.1
D.-5
B
)A.-1
B.5
C.1
D.-5
答案：B
解析：
$|-3| - (-2) = 3 + 2 = 5$
B
B
3.(2024·长沙)“玉兔号”是我国首辆月球车,它和着陆器共同组成“嫦娥三号”探测器.“玉兔号”月球车能够耐受月球表面的最低温度是$-180^{\circ }C$,最高温度是$150^{\circ }C$,则它能够耐受的温差是(
A.$-180^{\circ }C$
B.$150^{\circ }C$
C.$30^{\circ }C$
D.$330^{\circ }C$
D
)A.$-180^{\circ }C$
B.$150^{\circ }C$
C.$30^{\circ }C$
D.$330^{\circ }C$
答案：D
解析：
温差 = 最高温度 - 最低温度 = $150^{\circ}C - (-180^{\circ}C) = 150^{\circ}C + 180^{\circ}C = 330^{\circ}C$
D
D
4.填空:(1)$-3-6= $
(4)$(-3)-$
-9
; (2)$35-47= $-12
; (3)$(-5)-(-9)= $4
;(4)$(-3)-$
(-4)
$=1$; (5)5
$-7= -2$; (6)$-5-$(-5)
$=0$.答案：(1)-9 (2)-12 (3)4 (4)(-4) (5)5 (6)(-5)
5.计算:(1)$2-|-3|=$
(3)$-\frac {1}{2}-(-1)=$
-1
; (2)$(-1.2)-2\frac {1}{8}=$-3.325
;(3)$-\frac {1}{2}-(-1)=$
$\frac{1}{2}$
; (4)$|-14|-|+12|=$2
.答案：(1)-1 (2)-3.325 (3)$\frac{1}{2}$ (4)2
解析：
(1)$2 - |-3| = 2 - 3 = -1$
(2)$(-1.2) - 2\frac{1}{8} = -1.2 - 2.125 = -3.325$
(3)$-\frac{1}{2} - (-1) = -\frac{1}{2} + 1 = \frac{1}{2}$
(4)$|-14| - |+12| = 14 - 12 = 2$
(2)$(-1.2) - 2\frac{1}{8} = -1.2 - 2.125 = -3.325$
(3)$-\frac{1}{2} - (-1) = -\frac{1}{2} + 1 = \frac{1}{2}$
(4)$|-14| - |+12| = 14 - 12 = 2$
6.已知 A 地的海拔是 51m,B 地的海拔是-14m,C 地的海拔是-105m,则 A,B,C 三地中,地势最高的地方比地势最低的地方高
156
m.答案：156
解析：
51 - (-105) = 51 + 105 = 156
156
156
7.计算:
(1)$4.8-(-5.6)$;
(2)$(-4\frac {1}{2})-5\frac {3}{4}$;
(3)$2\frac {3}{4}-10\frac {2}{3}$;
(4)$|-1.8|-|-6.2|$;
(5)$(-3\frac {1}{4})-(+2\frac {1}{2})$;
(6)$-|-3\frac {3}{4}|-(-2\frac {1}{4})$.
(1)$4.8-(-5.6)$;
(2)$(-4\frac {1}{2})-5\frac {3}{4}$;
(3)$2\frac {3}{4}-10\frac {2}{3}$;
(4)$|-1.8|-|-6.2|$;
(5)$(-3\frac {1}{4})-(+2\frac {1}{2})$;
(6)$-|-3\frac {3}{4}|-(-2\frac {1}{4})$.
答案：(1)10.4 (2)$-10\frac{1}{4}$ (3)$-\frac{95}{12}$ (4)-4.4 (5)$-5\frac{3}{4}$ (6)$-\frac{3}{2}$
解析：
(1)$4.8 - (-5.6) = 4.8 + 5.6 = 10.4$;
(2)$(-4\frac{1}{2}) - 5\frac{3}{4} = -\frac{9}{2} - \frac{23}{4} = -\frac{18}{4} - \frac{23}{4} = -\frac{41}{4} = -10\frac{1}{4}$;
(3)$2\frac{3}{4} - 10\frac{2}{3} = \frac{11}{4} - \frac{32}{3} = \frac{33}{12} - \frac{128}{12} = -\frac{95}{12}$;
(4)$|-1.8| - |-6.2| = 1.8 - 6.2 = -4.4$;
(5)$(-3\frac{1}{4}) - (+2\frac{1}{2}) = -\frac{13}{4} - \frac{5}{2} = -\frac{13}{4} - \frac{10}{4} = -\frac{23}{4} = -5\frac{3}{4}$;
(6)$-|-3\frac{3}{4}| - (-2\frac{1}{4}) = -\frac{15}{4} + \frac{9}{4} = -\frac{6}{4} = -\frac{3}{2}$.
(2)$(-4\frac{1}{2}) - 5\frac{3}{4} = -\frac{9}{2} - \frac{23}{4} = -\frac{18}{4} - \frac{23}{4} = -\frac{41}{4} = -10\frac{1}{4}$;
(3)$2\frac{3}{4} - 10\frac{2}{3} = \frac{11}{4} - \frac{32}{3} = \frac{33}{12} - \frac{128}{12} = -\frac{95}{12}$;
(4)$|-1.8| - |-6.2| = 1.8 - 6.2 = -4.4$;
(5)$(-3\frac{1}{4}) - (+2\frac{1}{2}) = -\frac{13}{4} - \frac{5}{2} = -\frac{13}{4} - \frac{10}{4} = -\frac{23}{4} = -5\frac{3}{4}$;
(6)$-|-3\frac{3}{4}| - (-2\frac{1}{4}) = -\frac{15}{4} + \frac{9}{4} = -\frac{6}{4} = -\frac{3}{2}$.
8.(2024秋·宁波期中)规定$[x]$表示不超过x的整数中最大的整数,如$[5.34]= 5,[-1.24]= -2$,则$[4.6]-[-π]$的结果为(
A.1.46
B.1
C.8
D.7
C
)A.1.46
B.1
C.8
D.7
答案：C
解析：
$[4.6]=4$，$[-π]=-4$，$[4.6]-[-π]=4-(-4)=8$，答案选C。
9.用“＞”“＜”或“=”填空:
(1)若$a＞b$,则$a-b$
(2)若$a\lt b$,则$a-b$
(3)若$a= b$,则$a-b$
(4)若$a＜0,b＜0$,则$a-(-b)$
(1)若$a＞b$,则$a-b$
＞
0;(2)若$a\lt b$,则$a-b$
＜
0;(3)若$a= b$,则$a-b$
=
0;(4)若$a＜0,b＜0$,则$a-(-b)$
＜
0.答案：(1)＞ (2)＜ (3)= (4)＜