ta có 1/2 - 1/3 + 1/4 -1/6 = 1/6 +1/4 - 1/6 = 1/4   ( giải thích chút nha : hiệu của 1/2 với 1/3 bằng 1/6) 

bang 1/4 ban nhe

ta có 1/2-1/3+1/4-1/6= (3/6-2/6)+1/4-1/6

                              = 1/6+1/4-1/6

                              = 1/4

\(\text{Ta có: }1-\frac{1}{2}-\frac{1}{4}-\frac{1}{8}-\frac{1}{16}\)

\(=1-\left(1-\frac{1}{2}\right)-\left(\frac{1}{2}-\frac{1}{4}\right)-\left(\frac{1}{4}-\frac{1}{8}\right)-\left(\frac{1}{8}-\frac{1}{16}\right)\)

\(=\left(1-1\right)+\left(\frac{1}{2}-\frac{1}{2}\right)+\left(\frac{1}{4}-\frac{1}{4}\right)+\left(\frac{1}{8}-\frac{1}{8}\right)+\frac{1}{16}\)

\(=\frac{1}{16}\)

1-1/2-1/4-1/8-1/16

=1- 15/16

=16/16-15/16

=16-15/16

=1/16

1-1/2-1/4-1/8-1/16 =1-8/16-4/16-2/16-1/16=1/16

\(\frac{5}{6}-\left(\frac{2}{5}+\frac{1}{3}\right)\)

\(=\frac{5}{6}-\frac{11}{15}\)

\(=\frac{1}{10}\)

tíc mình nha

\(\frac{5}{6}-\left(\frac{2}{5}+\frac{1}{3}\right)=\frac{5}{6}-\frac{11}{15}=\frac{1}{10}\)

\(\frac{5}{6}\)-(\(\frac{2}{5}\)+\(\frac{1}{3}\))

=\(\frac{5}{6}\)-\(\frac{11}{15}\)

=\(\frac{1}{10}\)

Chuc ban hoc gioi!

/ là gì vậy em..giải thích đi chị trả lời cho

39x49 - 1 trên 35x48 + 34 

Tính bằng cách thuật tiện nhất. Ạ

= 955/875 em

chắc chắn đúng k chị nha

Câu cuối:

= 3 / 5 + 2 / 5 + ( 3 / 4 + 5 / 8 + 1 / 2 )

= 1 + ( 6 + 5 + 4 / 8 )

= 1 + 15 / 8

= 23 / 8 = \(2\frac{7}{8}\)

 4,8+4.8x3+4.8

= 4,8\(\times\)1 +4,8 \(\times\)3 +4,8\(\times\)1

=4,8 \(\times\)(3 + 1 + 1)

= 4,8\(\times\) 5

 = 24

chúc bn học tốt

\(4,8+4,8\cdot3+4.8\)

\(=4,8\cdot\left(3+1+1\right)\)

\(=4,8\cdot5\)

\(=24\)

a) \(\frac{2}{3}+\frac{3}{4}+\frac{4}{5}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}\)

= \(\left(\frac{2}{3}+\frac{1}{3}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{4}{5}+\frac{1}{5}\right)\)

= \(\frac{3}{3}+\frac{4}{4}+\frac{5}{5}\)

= \(1+1+1\)

= \(3\)

b) \(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{4}{6}+\frac{9}{12}+\frac{16}{20}\)

= \(\left(\frac{1}{3}+\frac{4}{6}\right)+\left(\frac{1}{4}+\frac{9}{12}\right)+\left(\frac{1}{5}+\frac{16}{20}\right)\)

= \(\left(\frac{1}{3}+\frac{2}{3}\right)+\left(\frac{1}{4}+\frac{3}{4}\right)+\left(\frac{1}{5}+\frac{4}{5}\right)\)

= \(\frac{3}{3}+\frac{4}{4}+\frac{5}{5}\)

= \(1+1+1\)

= \(3\)

ko sai được... đúng 100%

a)2/3+3/4+4/5+1/3+1/4+1/5

= ( 2/3 + 1/3 ) + ( 3/4 + 1/4 ) + ( 4/5 + 1/5 )

= 1 + 1 + 1 = 3

b) 1/3 + 1/4 + 1/5 + 4/6 + 9/12 + 16/20

= 1/3 + 1/4 + 1/5 + 2/3 + 3/4 4/5

= ( 1/3 + 2/3 ) + ( 1/4 + 3/4 ) + ( 1/5 + 4/5 ) 

= 1 + 1 + 1 = 3

a)  \(\left(\frac{2}{3}+\frac{1}{3}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{4}{5}+\frac{1}{5}\right)\)

=1+1+1

=3

b)  Tương tự vì\(\frac{4}{6}=\frac{2}{3};\frac{9}{12}=\frac{3}{4};\frac{16}{20}=\frac{4}{5}\)