1)69.24+69.120+144.31

= 69. (24+120) + 144.31

= 144.69 + 144.31

= 144. (69+31)

= 144.100

=14 400

2)95.103-95.2-95

= 95. (103-2-1)

= 95.100

= 9 500

4)47.62+31.106

= 47. 62+ (31.2). 53

= 47.62 + 62. 53

= 62. (47+53)

= 62.100

= 6 200

5) 54.12+27.77-27

= 27. (2.12) + 27.77 - 27.1

= 27. 24 + 27.77 - 27.1

= 27. (24+77-1)

= 27. 100

= 2 700

6) 49+215+51+83+85

= (49+51) + (215+85)+ 83

= 100 +300 + 83

= 483

− 5 12 + 6 11 + 7 17 + 5 11 + 5 12 = − 5 12 + 5 12 + 6 11 + 5 11 + 7 17 = 0 + 1 + 7 17 = 24 17

Sửa đề: 4^10

\(\dfrac{4^{10}\cdot9^3-6^9\cdot120}{8^4\cdot3^{12}+6^{11}}\)

\(=\dfrac{2^{20}\cdot3^6-2^{12}\cdot3^{10}\cdot5}{2^{12}\cdot3^{12}+2^{11}\cdot3^{11}}\)

\(=\dfrac{2^{12}\cdot3^6\left(2^8-3^4\cdot5\right)}{2^{11}\cdot3^{11}\left(2\cdot3+1\right)}=\dfrac{2}{3^5}\cdot\dfrac{-149}{7}=\dfrac{-298}{3^5\cdot7}\)

A = 5 11 + − 3 7 + 6 11 + 2 3 + − 4 7 = 5 11 + 6 11 + − 3 7 + − 4 7 + 2 3 = 2 3

N =  1 3

a)  − 5 11 + − 6 11 + 2 = − 5 11 + − 6 11 + 2 = − 1 + 2 = 1

b)  − 1 32 + 1 2 + − 15 32 = − 1 32 + − 15 32 + 1 2 = − 1 2 + 1 2 = 0