15: Tính:
a. 100 + (+430) + 2145 + (-530)
b. (-12) .15
c. (+12).13 + 13.(-22)
d. {[14 : (-2)] + 7} : 201
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a , 100 + ( + 430 ) + 2145 + ( - 530 ) = 530 + 2145 - 530 = ( 530 - 530 ) + 2145 = 0 + 2145 = 2145
b , ( - 12 ) . 15 = - ( 12 . 15 ) = - 180
c , ( + 12 ) . 13 + 13.( - 22 ) = 13 . [ ( + 12 ) + ( - 22 ) ] = 13 . ( - 10 ) = - 130
d , { [ 14 : ( - 2 ) ] + 7 } : 2012 = { ( - 7 ) + 7 } : 2012 = 0 : 2012 = 0
1 tính
a 100 + (+430) + 2145 + (-530)
b (-12) . 15
c (+12) . 13 + 13 . (-22)
d {[ 14 : (-2)] + 7} : 2012
\(a,100+\left(+430\right)+2145+\left(-530\right)\)
\(=100+430+2145-530\)
\(=\left(100+2145\right)+\left(430-530\right)\)
\(=2245+\left(-100\right)\)
\(=2245-100\)
\(=2145\)
\(b,,\left(-12\right).15\)
\(=-180\)
\(c,\left(+12\right).13+13.\left(-22\right)\)
\(=13.\left[12-22\right]\)
\(=13.\left(-10\right)\)
\(=-130\)
\(d.\left\{\left[14:\left(-2\right)\right]+7\right\}:2012\)
\(=\left\{-7+7\right\}:2012\)
\(=0:2012\)
\(=0\)
a. 100 + (+430) + 2145 + (–530)
= (100+2145) +[+430+(-530)]
=2245+(-100)
=2145
a) 100 + (+430) + 2145+ (-530)
= 100+ 430 + 2145 - 530
= 530 - 530 +2145
= 0 + 2145 = 2145
b) (-12).15 = -10.15 -2.15 = -150 - 30 = -180
c) (+12).13 + 13.(-22)
= 13. (12 - 22)
= 13. (-10)
= -130
d) {[14 : (-2)] + 7} : 2020
= { - 7 + 7} : 2020
= 0 : 2020
=0
Học tốt
a) 100 + (+430) + 2145 + (-530)
= 100 + [ (+430) + (-530) ] + 2145
= 100 + (-100) +2145
= 0 + 2145 = 2145
b) (-12) . 15 . 8 . (-4)
= [ (-12) . 8 ] . [ 15. (-4)]
= (-96) . (-60) = 5760
c) (+12) . 13 + 13 . (-22)
= 13. [ (+12) + (-22) ]
= 13. (-10) = -130
d) { [14 : (-2)] + 7 } : 2012
= { [ (-7) + 7 } : 2012
= 0 : 2012 = 0
e) -23 . 63 + 23 . 21 - 58 . 23
= 23 . -63 + 23 . 21 - 58.23
= 23. ( -63 + 21 - 58 )
= 23 . -100 = -2300
Hok tốt !
a) 100 + (+430) + 2145 + (-530)
=100+[430+(-530)]+2145
=100+(-100)+2145
=0+2145
=2145
b) (-12) . 15 . 8 . (-4)
=(-12.8).[15.(-4)]
=-90.(-60)
=5760
c) (+12) . 13 + 13 . (-22)
=13.[12+(-22)]
=13.(-10)
=-130
d) { [14 : (-2)] + 7 } : 2012
={-7+7}:2012
=0:2012
=0
e) -23 . 63 + 23 . 21 - 58 . 23
=23.(-63)+23.21-58.23
=23.(-63+21-58)
=23.(-100)
=-2300
12) 17 – 11 – 14 – (-39)
=17-11-14+39
=6-14+39
=-8+39
=31
13) −127 - 18.( 5 - 6)
=-127-18.1
=-145
14) 100 + (+430) + 2145 + (-530)
=530+2145-530
=(530-530)+2145
=0+2145
=2145
15) (+12).13 + 13.(-22)
=13.[12+(-22)]
=13.(-10)
=-130
16) {[14 : (-2)] + 7} : 2012
={-7+7}:2012
=0:2012
=0
17) 13 – 18 – (- 42) - 15
=13-18+42-15
=-5+42-15
=37-15
=22
18) 369 – 4[(-5) + 4.(-8)]
=369-4[-5+(-32)]
=369-4(-37)
=369+148
=517
19) (-12).(-13) +13.(-29)
=12.13+13.(-29)=13.[12+(-29)]=13.(-17)=-221
20) 125 – 4[ 3 – 7.(-2) ]
=125-4[3+14]
=125-4.17
=125-68
=57
21) (-14).9 – 13.(-9)
=(-14).9+13.9
=9.[-14+13]
=9.(-1)
=-9
Tính dễ thì tự làm nha
2) Tìm x
a) Sửa đề:
\(\left|x\right|=10+-3\)
\(\left|x\right|=7\)
\(\Leftrightarrow x=\left\{\pm7\right\}\)
b)
\(\left|x\right|< 6\)
\(0\le\left|x\right|\)
\(\Leftrightarrow0\le\left|x\right|< 6\)
\(\left|x\right|\in\left\{0;1;2;3;4;5\right\}\)
\(x\in\left\{\pm1;\pm2;\pm3;\pm4;\pm5\right\}\)
Tổng là:
\(-5+-4+....+3+4+5\)
\(=\left(-5+5\right)+\left(-4+4\right)+\left(-3+3\right)+\left(-2+2\right)+\left(-1+1\right)+0=0\)
a) 100+530+2145+(-630)
=100+(530-630)+2145
=100-100+2145
=2145
b)15.(-12)=-180
c) 14.13+13.(-24)
=13.(14-24)
=13.(-10)
=-130
d){[14:(-2)]+7}:2018
=[(-7)+7]:2018
=0:2018
=0
a) 100 +430 +2145+(-530)
=(100+2145) +[ 430+(-530)]
=2245 + (-100) =2145
b) (-12). 15 = -(12.15)= -180