a,  15 . { 32 : [ 6 - 5 + 5 ( 9 : 3 ) ] + 3 } - 2018 0

= 15.{32:[1+15]+3}–1

= 15.5–1

= 74

b,  25 . { 2 7 : [ 12 - 4 + 2 2 . 16 : 2 3 ] - 2 4 }

= 25.{128:[8+4.2]–16}

= 25.24

= 600

c,  2019 . { 101 - 1000 : [ 2 2 . 2 3 + 5 6 : 5 3 - 6 2 : 11 - 2018 0 ] }

= 2019.{101–1000:[(32+125–36):11–1]}

= 2019.{101–1000:[121:11–1]}

= 2019.{101–1000:10}

= 2019.1

= 2019

a. \(\left(-37\right)+14+26+37\)

\(=\left[\left(-37\right)+37\right]+\left(14+26\right)\)

\(=0+40\)

\(=40\)

b. \(\left(-24\right)+6+10+24\)

\(=\left[\left(-24\right)+24\right]+6+10\)

\(=0+6+10\)

\(=16\)

c. \(15+23+\left(-25\right)+\left(-23\right)\)

\(=\left[\left(-25\right)+15\right]+\left[\left(-23\right)+23\right]\)

\(=-10+0\)

\(=-10\)

các câu khác bn tự lm

d. \(35\cdot18-5\cdot7\cdot28\)

\(=35\cdot18-35\cdot28\)

\(=35\cdot\left(18-28\right)\)

\(=35\cdot\left(-10\right)\)

\(=-350\)

câu e, f, g bn tự lm

a)\(\frac{-212}{351}\)

b)\(\frac{29}{10}\)

c)thiếu đề

\(\frac{3}{4}.\frac{8}{9}.\frac{15}{16}.\frac{24}{25}...\frac{63}{64}\)

\(=\frac{1.3}{2.2}.\frac{2.4}{3.3}.\frac{3.5}{4.4}.\frac{4.6}{5.5}...\frac{7.9}{8.8}\)

\(=\frac{1.3.2.4.3.5.4.6...7.9}{2.2.3.3.4.4.5.5...8.8}\)

\(=\frac{1.9}{2.8}=\frac{9}{16}\)

Hê lô

a) \(L=4-8+12-16+20-24+...+220-224\)

\(\Rightarrow L=\left(-4\right)+\left(-4\right)+\left(-4\right)+...+\left(-4\right)\) (có 28 số -4)

\(\Rightarrow L=\left(-4\right).28=-112\)

c) \(O=6-12+18-24+30-36+354-360\) 

\(\Rightarrow O=\left(-6\right)+\left(-6\right)+\left(-6\right)+...+\left(-6\right)\) (có 30 số -6)

\(\Rightarrow O=\left(-6\right).30=-180\)

e) \(P=3-6+9-12+15-18+...+147-150\)

\(\Rightarrow P=\left(-3\right)+\left(-3\right)+\left(-3\right)+...+\left(-3\right)\) (có 25 số -3)

\(\Rightarrow P=\left(-3\right).25=-75\)

b)

S = 3 + 5 - 7 - 9 + 11 + 13 - 15 - 17 + ... + 243 + 245 - 247 - 249

S = (3 - 7) + (5 - 9) + ... + (243 - 247) + (245 - 249)

S = (-4) + (-4) + ... + (-4) + (-4)

Tổng trên có số số hạng là : [(249 - 3) : 2 + 1] : 2 = 62 (số hạng)

Suy ra S = (-4) x 62 = -248

d)

E = 2 - 4 + 6 - 8 + ... + 218 - 220

E = (2 - 4) + (6 - 8) + ... + (218 - 220)

E = (-2) + (-2) + ... + (-2)

Tổng trên có số số hạng là: [(220 - 2) : 2 + 1] : 2 = 55 (số hạng)

Suy ra E = (-2) x 55 = -110

\(a,\frac{11}{12}:\frac{7}{24}\cdot\frac{21}{24}=\frac{11\cdot24\cdot7\cdot3}{4\cdot3\cdot7\cdot24}=\frac{11}{4}\)

\(b,\frac{5}{12}:\frac{7}{4}-\frac{25}{18}:\frac{35}{6}=\frac{5\cdot4}{3\cdot4\cdot7}-\frac{5\cdot5\cdot6}{6\cdot3\cdot5\cdot7}=\frac{5}{21}\)

Đặt \(A=15+2^4+2^5+...+2^{2020}\)

\(A=1+2+2^2+2^3+2^4+...+2^{2020}\)

\(2A=2+2^2+2^3+...+2^{2021}\)

\(\Rightarrow2A-A=2^{2021}-1\)

\(\Rightarrow A=2^{2021}-1\)

a. 215 - 5 + 10 = 210 + 10 = 220

b. 13 + (-17) = -4

c. 25 . 5 . 2014 . 4 . 2 = (25 . 4) . (5 . 2) . 2014 = 100 . 10 . 2014 = 1000 . 2014 = 2014000

đ. 24.35 + 76.35 - 500 = (24 + 76) . 35 - 500 = 100 . 35 - 500 = 3500 - 500 = 3000

e. 3 + 7 + 11 + 15 + ... + 399 + 403 = 406 . 101 : 2 = 20503