\(\frac{3}{4}+6,8+0,25+0,5+\frac{1}{2}+\frac{1}{5}=\left(\frac{3}{4}+0,25\right)+\left(6,8+\frac{1}{5}\right)+\left(0,5+\frac{1}{2}\right)\)

                                                                  \(=\left(\frac{3}{4}+\frac{1}{4}\right)+\left(\frac{34}{5}+\frac{1}{5}\right)+\left(\frac{1}{2}+\frac{1}{2}\right)\)

                                                                  \(=1+7+1=9\)

3/4 + 6,8 + 0,25 + 0,5 + 1/2 + 1/5 

= 9

Chúc bn hok tốt

Ta có : 

\(\frac{3}{4}+\frac{6}{8}+0,25+0,5+\frac{1}{2}+\frac{1}{5}\)

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

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

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

\(=1,25+1+0,2\)

\(=2,25+0,2\)

\(=2,45\)

\(\left(6\dfrac{2}{5}+0,5\right):\dfrac{1}{4}+\dfrac{2}{5}\)

\(=\left(\dfrac{32}{5}+\dfrac{1}{2}\right):\dfrac{1}{4}+\dfrac{2}{5}\)

\(=\left(\dfrac{64}{10}+\dfrac{5}{10}\right)\times4+\dfrac{2}{5}\)

\(=\dfrac{69}{10}\times4+\dfrac{2}{5}\)

\(=\dfrac{276}{10}+\dfrac{2}{5}=\dfrac{138}{5}+\dfrac{2}{5}\)

\(=\dfrac{140}{5}=28\)

___________________________________________

\(32\times\dfrac{4}{5}+6,8\)

\(=32\times\dfrac{4}{5}+\dfrac{34}{5}\)

\(=\dfrac{128}{5}+\dfrac{34}{5}\)

\(=\dfrac{162}{5}\)

Câu 1.0,5+0,5=1

Câu 2.0,25+0,25=0,5

Câu 3.0,125+0,125=0,25

Câu 4.0,0625+0,0625=0,125

Câu 5.15,39+25,5=40,89

1.=1

2.=0,5

3.=0,25

4.=0,125

5.=4089.

câu 1 ; 1

câu 2: 0,5

câu 3;0.25

câu 4 : 0.125

câu 5 :40,89

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

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

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

a) 11 : 4 + 5,3 x 3,8
= 3,75 + 5,3 x 3,8
= 3,75 + 20,14
= 23,89
b) 16,52 : 0,5 - 2,7 : 0.25
= 33,04 - 2,7 : 0,25
= 33,04 - 10,8
= 22,24
c) 7/5 : 2/3 : 1,05 - 4/9
= 7/5 : 2/3 : 21/20 - 4/9
= 7/5 x 3/2 x 20/21 - 4/9
= (1 x 3 x 2)/ (1 x 1 x 3)
= 6/3
= 2

a 2.75+20.4=22.89

b 33.04-10.8=22.24

a) 11 : 4 + 5,3 x 3,8
= 2,75 + 5,3 x 3,8
= 2,75 + 20,14
= 22,89
b) 16,52 : 0,5 - 2,7 : 0.25
= 33,04 - 2,7 : 0,25
= 33,04 - 10,8
= 22,24
c) 7/5 : 2/3 : 1,05 - 4/9
= 7/5 : 2/3 : 21/20 - 4/9
= 7/5 x 3/2 x 20/21 - 4/9
= (1 x 3 x 2)/ (1 x 1 x 3)
= 6/3
= 2

a)4x-3=4-3x

<=>4x+3x=4+3

<=>7x=7

<=>x=1

\(\text{b)3+x-5=}6x-4\Leftrightarrow x-6x=-4+5-3\Leftrightarrow-5x=-2\Leftrightarrow x=\dfrac{2}{5}\)

vậy S=\(\left\{\dfrac{2}{5}\right\}\)

do ngu

1) 2,75 - 5/6 × 2/5 = 2,75 - (5/6) × (2/5) = 2,75 - 1/3 = 2,75 - 0,33 = 2,42

2) 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 3/4) - 3/5 = 1,25 - (5/6 - 9/12) - 3/5 = 1,25 - (10/12 - 9/12) - 3/5 = 1,25 - 1/12 - 3/5 = 1,25 - 0,08 - 0,6 = 1,25 - 0,68 = 0,57

3) 4/9 × 0,75 + 8/5 + 3,125 = (4/9) × 0,75 + 8/5 + 3,125 = 0,44 + 8/5 + 3,125 = 0,44 + 1,6 + 3,125 = 0,44 + 4,725 = 5,165

4) 1,125 - 4/7 - 0,12 = 1,125 - (4/7) - 0,12 = 1,125 - 0,57 - 0,12 = 0,435 - 0,12 = 0,315

5) (1/3 + 0,4) × 3,5 + (1/6 + 0,75) × 6/5

a)   \(4x-3=4-3x\)

\(\Leftrightarrow\)\(7x=7\)

\(\Leftrightarrow\)\(x=7\)

Vậy...

b)    \(3+\left(x-5\right)=2\left(3x-2\right)\)

\(\Leftrightarrow\)\(3+x-5=6x-4\)

\(\Leftrightarrow\)\(5x=2\)

\(\Leftrightarrow\)\(x=\frac{2}{5}\)

Vậy...