a) ( 127 - 34 ) - ( 127 - 54 - 34 )

= 93 - ( 127 - 54 - 34 )

= 93 - 39

= 54

Cách này ko nhanh !

a) ( 127 - 34 ) - ( 127 - 54 - 34 )

= 54 - ( 127 - 127 ) - ( 34 - 34 ) 

= 54 - 0 - 0

= 54

Học tốt nhé !

Cách này của tớ đúng đấy

Đặt A = 1 + 3² + 3⁴ +...+ 3²⁰¹⁸

\(\Rightarrow\) 3²A = 9A = 3² + 3⁴ + 3⁶ + ... + 3²⁰²⁰

\(\Rightarrow\) 9A - A = 8A = 3²⁰²⁰ - 1

\(\Rightarrow\) A = \(\dfrac{3^{2020}-1}{8}\)

Vậy 1 + 3² + 3⁴ +...+ 3²⁰¹⁸  =  \(\dfrac{3^{2020}-1}{8}\)

\(17.\left(\dfrac{5}{17}-\dfrac{1}{34}+\dfrac{1}{2}\right)=17.\left(\dfrac{10}{34}-\dfrac{1}{34}+\dfrac{17}{34}\right)=17.\dfrac{26}{34}=13\)

\(#PaooNqoccc\)

\(17.\left(\dfrac{5}{17}-\dfrac{1}{34}+\dfrac{1}{2}\right)\)

\(=17.\left(\dfrac{10}{34}-\dfrac{1}{35}+\dfrac{1}{2}\right)\)

\(=17.\left(\dfrac{9}{34}+\dfrac{1}{2}\right)\)

\(=17.\left(\dfrac{9}{34}+\dfrac{17}{34}\right)\)

\(=17.\dfrac{13}{17}\)

\(=13\)

\(17.\left(\dfrac{5}{17}-\dfrac{1}{34}+\dfrac{1}{2}\right)\\ =\dfrac{17.5}{17}-\dfrac{17}{34}+\dfrac{17}{2}\\ =5-\dfrac{1}{2}+\dfrac{17}{2}\\ =\dfrac{9}{2}+\dfrac{17}{2}\\ =\dfrac{26}{2}=13\)

\(34\times65+34\times13+34\)
\(=34\times\left(65+34+1\right)\)
\(=34\times100\)
\(=3400\)
#DatNe

=34(65+13+1)

=34*79

=2686

\(\dfrac{34}{50}-\dfrac{3}{8}+\dfrac{1}{4}=\dfrac{34\times4}{200}-\dfrac{3\times25}{200}+\dfrac{50}{200}=\dfrac{136-75+50}{200}=\dfrac{111}{200}\)

= 34 * 67 + 34 * 32  + 34 *1

= 34 * ( 67 + 32 + 1 ) 

= 34 * 100

 = 3400

k cho tui nhé

34*67 + 34*32 + 34

= 34*( 67 + 32 + 1)

= 34*100

= 3400

34   .   ( − 84 ) + 16   .   ( − 34 ) = 34   .   ( − 84 ) + ( − 16 )   .   34 = 34   .   ( − 84 ) + ( − 16 ) = 34   .   ( − 100 ) = − 3400.

1.202200

2.3780

\(2022\cdot99+2022=2022\left(99+1\right)=2022\cdot100=202200\)

\(135\cdot3^3+5\left(3^3\cdot4-3^4\right)\)

\(=135\cdot3^3+5\cdot3^3\cdot4-5\cdot3^4\)

\(=3^3\cdot\left(135+5\cdot4-5\cdot3\right)=3^3\cdot140=1260\)

1.  Tính nhanh :
2022 . 99 + 2022
= 2022 . (99 + 1)
= 2022 . 100
= 202200

2. Thực hiện phép tính :
135 . 3³ + 5 . ( 3³. 4 - 3⁴ )
= 135 . 27 + 5 . ( 27 . 4 - 81 )
= 3645 + 5 . ( 108 - 81 )
= 3645 + 5 . 27
= 3645 + 135
= 3780