问题
解答题
(1)-7+(+2) (2)0-(-5) (3)(-49)-(+91)-(-5)+(-9) (4)-7+13-6+20 (5)(-1
(6)(-5)×(-4
(7)
(8)(-5)×(-7)×2×(-6) (9)(-
(10)19
(11)(-0.125)×0.5×(-100)×8 (12)3×(-2
(13)-22×(-
|
答案
(1)-7+(+2)=-5;
(2)0-(-5)=5;
(3)(-49)-(+91)-(-5)+(-9)
=-49-91+5-9
=-149+5
=-144;
(4)-7+13-6+20
=-13+33
=20;
(5)(-1
)-11 2
+(-21 4
)-(-31 2
)-(-13 4
)1 4
=(-1
-21 2
)+(-11 2
+11 4
+31 4
)3 4
=-4+33 4
=-
;1 4
(6)(-5)×(-4
)=21;1 5
(7)
÷(-23 7
)=-1 7
;1 5
(8)(-5)×(-7)×2×(-6)
=(-5×2)×[(-7)×(-6)]
=-10×42
=-420;
(9)(-
)×15×(-17 8
)1 7
=[(-
)×(-17 8
)]×151 7
=1×15
=15;
(10)19
×(-10)15 17
=(20-
)×(-10)2 17
=-200+13 17
=-188
;14 17
(11)(-0.125)×0.5×(-100)×8
=(-0.125×8)×[0.5×(-100)]
=-1×(-50)
=50
(12)3×(-2
)+2×(-21 3
)-5×(-1 3
)7 3
=(3+2-5)×(-
)7 3
=0×(-
)7 3
=0;
(13)-22×(-
)+8÷(-2)2.1 2
=-4×(-
)+8÷41 2
=2+2
=4.