chia ra làm các nhóm (13-12+11)+(10-9+8)-(7-6+5) -(4+3+2-1)

hay ta thấy 3 nhóm đầu có tổng  =số trừ trong các nhóm đó tức là 12+9-6+(4+3+2-1)

Hay= 23

ê câu này bằng13

a/  3 + 2387 : 77 - 33 

= 3 + 31 - 33

= 31 + ( 3 - 33)

= 31 + (-30)

= 1

b/ 8 x 33 x 25 x 125 x 4

= (8 x 125) x (4 x 25) x 33

= 1000 x 100 x 33

= 100000x 33

= 3300000

c/ 20, 16 : 0,01

= 2016 : 1

= 2016

Thêm : 

D, 8,6 - 2,75

E, 4\(\frac{3}{8}\)+ 5\(\frac{2}{3}\)

F, 3\(\frac{1}{5}\)- 1\(\frac{1}{5}\)+ \(\frac{2}{5}\)

G, \(\frac{2}{5}\)+ \(\frac{3}{5}\): \(\frac{4}{5}\)

H, \(\frac{5}{2}\)x \(\frac{1}{3}\)+ \(\frac{1}{4}\)

\(a,\frac{8^{2017}-8^{2015}}{8^{2014}.8}\)

\(=\frac{8^{2015}.\left(8^2-1\right)}{8^{2015}}\)

\(=64-1\)

\(=63\)

\(b,\frac{2^8+8^3}{2^5.2^3}\)

\(=\frac{2^8+\left(2^3\right)^3}{2^8}\)

\(=\frac{2^8+2^9}{2^8}\)

\(=\frac{2^8.\left(1+2\right)}{2^8}\)

\(=3\)

Học tốt

8²⁰¹⁷ - 8²⁰¹⁵ = 8²⁰¹⁵(8² - 1) = 8²⁰¹⁵.63

8²⁰¹⁴.8 = 8²⁰¹⁴⁺¹ = 8²⁰¹⁵

=> \(\frac{8^{2017}-8^{2015}}{8^{2014}\cdot8}=\frac{8^{2015}\cdot63}{8^{2015}}=63\)

2⁸ + 8³ = 2⁸ + (2³)³ = 2⁸ + 2⁹ = 2⁸(1 + 2) = 2⁸.3

2⁵.2³ = 2⁵⁺³ = 2⁸

=> \(\frac{2^8+8^3}{2^5\cdot2^3}=\frac{2^8\cdot3}{2^8}=3\)

a) 

\(=\left(8^{2017}-8^{2015}\right):\left(8^{2014}\cdot8\right)\) 

\(=8^{2015}\left(8^2-1\right):8^{2015}\) 

\(=8^{2015}\left(64-1\right):8^{2015}\cdot1\) 

\(=8^{2015}\cdot\left(64-1-1\right)\)   

\(=8^{2015}\cdot62\)    

b) 

\(=\left[2^8+\left(2^3\right)^3\right]:2^8\) 

\(=\left[2^8+2^9\right]:2^8\)  

\(=2^8\left(1+2^1\right):2^8\)  

\(=3\)

0.66 do ban

[ 219 + (-299)] + 12.5

= -80 + 60

= -20

\(\left[219+\left(-299\right)\right]+12.5\)

= \(\left(-80\right)+60\)

= \(-20\)

Hok tốt