mình gấp lắm ạ
{ 210 :[ 16 + 3.(6+3.22)]}-3
Toán lớp 6
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\(\left\{210:\left[16+3.\left(6+3.22\right)\right]\right\}-3\)
\(=\left\{210:\left[16+3.\left(6+66\right)\right]\right\}-3\)
\(=\left\{210:\left[16+3.72\right]\right\}-3\)
\(=\left\{210:\left[16+216\right]\right\}-3\)
\(=\left\{210:232\right\}-3\)
\(=\dfrac{105}{116}-3\)
\(=\dfrac{-243}{116}\)
\(\left\{210:\left[16+3.\left(6+3.2^2\right)\right]\right\}-3\)
\(=\left\{210:\left[16+3.\left(6+3.4\right)\right]\right\}-3\)
\(=\left\{210:\left[16+3.\left(6+12\right)\right]\right\}-3\)
\(=\left\{210:\left[16+3.18\right]\right\}-3\)
\(=\left\{210:\left[16+54\right]\right\}-3\)
\(=\left\{210:70\right\}-3\)
\(=3-3\)
\(=0\)
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B18:
1) \(\left(a-b+c\right)-\left(a+c\right)=a-b+c-a-c=-b\)
2) \(\left(a+b\right)-\left(b-a\right)+c=a+b-b+a+c=2a+c\)
3) \(-\left(a+b-c\right)+\left(a-b-c\right)=-a-b+c+a-b-c=-2b\)
4) \(a\left(b+c\right)-a\left(b+d\right)=ab+ac-ab-ad=ac+ad=a\left(c-d\right)\)
5) \(a\left(b-c\right)+a\left(d+c\right)=ab-ac+ad+ac=ab+ad=a\left(b+d\right)\)
1/ (a - b + c) - (a + c) = a - b + c - a - c
= (a - a) + (c - c) - b = -b
2/ (a + b) - (b - a) + c = a + b - b + a + c
= (a + a) + (b - b) + c = 2a + c
3/ - (a + b - c) + (a - b - c) = -a - b + c + a - b - c
= (-a + a) - (b + b) + (c - c) = -2b
4/ a(b + c) - a(b + d) = ab + ac - ab - ad
= (ab - ab) + (ac - ad)
= a(c - d)
5/ a(b - c) + a(c + d) = ab - ac + ac + ad
= (ab + ad) + (-ac + ac)
= a(b + d)
1: \(23+\left(-13\right)+\left(-50\right)\)
\(=23-13-50\)
=10-50
=-40
2: \(-5+15+\left(-123\right)\)
\(=\left(-5+15\right)-123\)
=10-123
=-113
3: \(5871:\left\{928-\left[\left(-82+247\right)\right]\right\}\cdot5\)
\(=5871-\left\{928+82-247\right\}\cdot5\)
\(=5871-763\cdot5=5871-3815=2056\)
4: \(40-\left(4\cdot5^2-3\cdot2^3\right)\)
\(=40-4\cdot5^2+3\cdot2^3\)
\(=40-4\cdot25+3\cdot8\)
=40-100+24
=64-100
=-36
5: \(6^2\cdot5-7^2+149\)
\(=36\cdot5-49+149\)
\(=180+149-49\)
=180+100
=280
6: \(-210:\left[16+3\cdot\left(6+3\cdot2^2\right)\right]+\left(-2022\right)\)
\(=-210:\left[16+3\cdot\left(6+3\cdot4\right)\right]+\left(-2022\right)\)
\(=-210:\left[16+3\cdot18\right]+\left(-2022\right)\)
\(=-210:70-2022\)
=-3-2022
=-2025
7: \(5\cdot2^3+7^{11}:7^9-2023^0\cdot1^8\)
\(=5\cdot8+7^2-1\)
=40+49-1
=39+49
=88
8: \(400:\left\{5\cdot\left[360-\left(290+2\cdot5^2\right)\right]\right\}\)
\(=400:\left\{5\cdot\left[360-290-2\cdot25\right]\right\}\)
\(=400:\left\{5\cdot20\right\}\)
\(=\dfrac{400}{100}=4\)
9: \(75-\left(3\cdot5^2\right)-4\cdot5^3\)
\(=75-3\cdot25-4\cdot5^3\)
=-4*125
=-500
ta có: 1/1*6+1/6*11+1/6*16+...+1/51*56.
=1/5.(5/1.6+5/6.11+5/6.16+...+5/51.56)
=1/5.(1/1-1/6+1/6-...-1/56)
=1/5.(1-1/56)
=1/5.(55/56)
=11/56
S2 = (2-4-6+8+10) - (12-14+16+18) - ....+(1994-1996-1998+2000)
= 0 + 0 + 0 + ..... + 0
= 0
Ta có: S1 = 2+4+6-8+............+1998-2000
= (2+4+6-8) +............+(1994 + 1996 + 1998 - 2000)
= 4 +