\(\dfrac{1}{2}:0,5-\dfrac{1}{4}:0,25+\dfrac{1}{5}:0,2-\dfrac{1}{8}:0,125\)

\(=\dfrac{1}{2}\times2-\dfrac{1}{4}\times4+\dfrac{1}{5}\times5-\dfrac{1}{8}\times8\)

\(=1-1+1-1=0\)

1)\(y\times7:5+4\times8=134\)

  \(\Leftrightarrow y\times7:5+32=134\)

  \(\Leftrightarrow y\times7:5=102\)

  \(\Leftrightarrow y\times7=510\)

  \(\Leftrightarrow y=72,86\)

2) \(\dfrac{1}{4}:0,25-\dfrac{1}{8}:0,125+\dfrac{1}{2}:0,5-\dfrac{1}{10}\)

\(=0,25:0,25-0,125:0,125+0,5:0,5-\dfrac{1}{10}\)

\(=1-1+1-\dfrac{1}{10}\)

\(=\dfrac{9}{10}\)

\(\dfrac{1}{2}:0,5+\dfrac{1}{4}:0,25+\dfrac{1}{8}:0,125\)

\(=\dfrac{1}{2}\times2+\dfrac{1}{4}\times4+\dfrac{1}{8}\times8\)

\(=\dfrac{2}{2}+\dfrac{4}{4}+\dfrac{8}{8}=1+1+1=3\)

1/2 : 0,5 + 1/4 : 0,25 + 1/8 :0,25

đổi 1/2=0,5;1/4=0,25;1/8=0,125

=0,5:0,5+0,25:0,25+0,125:0,125

=1+1+1

=3

\(=\dfrac{1}{4}:\dfrac{1}{4}-\dfrac{1}{8}:\dfrac{1}{8}+\dfrac{1}{2}:\dfrac{1}{2}-\dfrac{1}{10}\)

\(=1-1+1-\dfrac{1}{10}\)

= 0,9

\(\dfrac{1}{4}:0,25-\dfrac{1}{8}:0,125+\dfrac{1}{2}:0,5-\dfrac{1}{10}\\ =\dfrac{1}{4}:\dfrac{1}{4}-\dfrac{1}{8}:\dfrac{1}{8}+\dfrac{1}{2}:\dfrac{1}{2}-\dfrac{1}{10}\\ =1-1+1-\dfrac{1}{10}\\ =\left(1-1\right)+\left(1-\dfrac{1}{10}\right)\\ =1-\dfrac{1}{10}\\ =\dfrac{10-1}{10}=\dfrac{9}{10}\)

=1/4:1/4-1/8:1/8+1/2:1/2-1/10

=1-1+1-1/10

=1-1/10

=9/10

`1/4:0,25-1/8:0,125+1/2:0,5-1/10`

`=1/4 : 1/4 - 1/8 : 1/8 + 1/2 :1/2 - 1/10 `

`=1/4 . 4/1 - 1/8 . 8/1 + 1/2 . 2/1 - 1/10`

` = 1  - 1 + 1 - 1/10 `

`=  1 - 1/10 `

`= 10/10 - 1/10 `

`=9/10`

Không khó đâu nhé em:

\(75\%+\frac{1}{4}-\frac{1}{4}:0,25+\frac{1}{8}:0,125-\frac{1}{2}:0,5\)  

\(=\frac{3}{4}+\frac{1}{4}-\frac{1}{4}:\frac{1}{4}+\frac{1}{8}:\frac{1}{8}-\frac{1}{2}:\frac{1}{2}\)

\(=\frac{3}{4}+\frac{1}{4}-1+1-1\)

\(=1-1+1-1\)

\(=0\)

\(\dfrac{1}{2}:0,5+\dfrac{1}{4}:0,25-\dfrac{1}{10}:0,1+\dfrac{1}{8}:0,125\)

\(=\dfrac{1}{2}.2+\dfrac{1}{4}.4+\dfrac{1}{10}.10+\dfrac{1}{8}.8\)

\(=1+1+1+1=4\)

1/4:0,25-1/8:0,125+1/2:0,5-1/10:0,1

=1/4x4-1/8x8+1/2x2-1/10x10

=4/4-8/8+2/2-10/10

=1-1+1-1

=0