1+2+3+4+5+6+7+8+9+11+22+33+44+55+66+77+88+99=540

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8+ 9 + 11 + 22 + 33 + 44 + 55 + 66 + 77 + 88+ 99

= ( 1 + 2 + 3 + 4+ 5 + 6 + 7 + 8 + 9 ) + ( 11 + 22 + 33 + 44 + 55 +66 +77 + 88 + 99)

= 45                                                 +                   495

=      540

Đặt A=1+2+3+4+5+6+7+8+9

Số  các số hạng của A là 

9-1+1=9(so hang )

tổng A =(9+1).9:2=45

B=11+22+33+44+55+66+77+88+99

=495

vậy tổng 1+2+3+4+5+6+7+8+9+11+22+33+44+55+66+77+88+99=45+495=50

hoi vo van

đúng òi vớ va vớ vẩn

Đúng, tui đến đây để cho 1 báo cáo

11 = 1 

k cho mik nha

1=11

2=22

3=33

4=44

5=55

6=66

7=77

8=88

9=99

11=1

11=1 NHÉ BẠN

11  =1111

11=1 vì 1=11

11=1111 ban ha

a) 45

b) 459

c) 495

chúc bạn học tốt~

1+2+3+4+5+6+7+8+9=45

10+20+39+40+50+60+70+80+90=459(Chắc bạn bấm nhầm 30->39)

11+22+33+44+55+66+77+88+99=495

(a)45 (b)459 (c)495

1) \(=\frac{7}{4}.\left[\frac{2}{3}-\left(\frac{1}{2}-\frac{3}{8}\right)\right]=\frac{7}{4}.\left(\frac{2}{3}-\frac{1}{8}\right)=\frac{7}{4}.\frac{13}{24}=\frac{91}{96}\)

2) \(=\frac{3}{4}-\left[-\left(-\frac{5}{3}\right)-\left(\frac{1}{12}+\frac{2}{9}\right)\right]=\frac{3}{4}-\frac{5}{3}-\frac{-5}{36}=\frac{-11}{12}+\frac{5}{36}=\frac{-28}{36}\)

3) \(=-\frac{6}{11}+\frac{12}{-7}+\frac{-34}{77}=-\frac{42}{77}+\frac{-132}{77}+\frac{-34}{77}=\frac{-208}{77}\)

4) \(=\frac{1}{11}+\frac{2}{3}+\frac{-19}{33}=\frac{3}{33}+\frac{22}{33}+\frac{-19}{33}=\frac{6}{33}=\frac{3}{11}\)
 

Câu 2) Đinh Tuân việt nhầm:

Quy đồng \(\frac{1}{12}+\frac{2}{9}=\frac{3}{36}+\frac{8}{36}=\frac{11}{36}\)

=> Người chọn đáp án nên thấy hiểu và hợp lý  mới chọn

1=11  2=22     3=33    4=44   5=55    6=66    7=77    8=88 .... 11=1

như đề bài cho

Là bạn nè sao bây giờ mới lên vậy làm mk đợi 

vì 1=11 nên 11=1

`@` `\text {Ans}`

`\downarrow`

`a)`

\(\dfrac{1}{2}-\dfrac{5}{6}+\dfrac{11}{33}-\dfrac{35}{40}\)

`=`\(\dfrac{1}{2}-\dfrac{5}{6}+\dfrac{1}{3}-\dfrac{7}{8}\)

`=`\(\dfrac{12}{24}-\dfrac{20}{24}+\dfrac{8}{24}-\dfrac{21}{24}\)

`= -21/24 = -7/8`

`b)`

\(\dfrac{2}{3}\cdot1\dfrac{3}{4}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)

`=`\(\dfrac{2}{3}\cdot\dfrac{7}{4}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)

`=`\(\dfrac{7}{6}-\dfrac{8}{9}-\dfrac{17}{51}-\dfrac{1}{5}\)

`=`\(\dfrac{5}{18}-\dfrac{17}{51}-\dfrac{1}{5}\)

`=`\(-\dfrac{1}{18}-\dfrac{1}{5}=-\dfrac{23}{90}\)

`c)`

\(\dfrac{1}{2}\cdot2-2\dfrac{5}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)

`=`\(1-\dfrac{19}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)

`=`\(-\dfrac{12}{7}+\dfrac{6}{4}-\dfrac{10}{15}\)

`=`\(-\dfrac{3}{14}-\dfrac{10}{15}=-\dfrac{37}{42}\)

`d) `

\(\dfrac{1}{6}\cdot\dfrac{1}{11}+\dfrac{4}{11}\cdot\left(-\dfrac{1}{6}\right)+\dfrac{8}{11}\cdot\dfrac{1}{6}+\dfrac{1}{6}\cdot\dfrac{6}{11}\)

`=`\(\dfrac{1}{6}\cdot\left(\dfrac{1}{11}-\dfrac{4}{11}+\dfrac{8}{11}+\dfrac{6}{11}\right)\)

`=`\(\dfrac{1}{6}\cdot\left(\dfrac{1-4+8+6}{11}\right)\)

`=`\(\dfrac{1}{6}\cdot1=\dfrac{1}{6}\)

`e)`

\(-17\cdot\left(-23\right)+\left(-53\right)\cdot17+17\cdot14+17\cdot\left(-24\right)\)

`= 17*(23-53+14-24)`

`= 17*(-40)`

`= -680`

`f)`

\(-19\cdot218+\left(-82\right)\cdot19-533\cdot19+\left(-19\right)\cdot167\)

`= 19*(-218-82-533-167)`

`= 19*(-1000)`

`= -19000`

`g)`

\(\dfrac{2}{5}+\dfrac{3}{8}-\dfrac{11}{44}+\dfrac{9}{16}\)

`=`\(\dfrac{2}{5}+\dfrac{3}{8}-\dfrac{1}{4}+\dfrac{9}{16}\)

`=`\(\dfrac{31}{40}-\dfrac{1}{4}+\dfrac{9}{16}\)

`=`\(\dfrac{21}{40}+\dfrac{9}{16}=\dfrac{87}{80}\)

`h)`

\(\dfrac{4}{10}-1\dfrac{5}{6}\cdot2+\dfrac{7}{8}-\dfrac{1}{9}\)

`=`\(\dfrac{4}{10}-\dfrac{11}{6}\cdot2+\dfrac{7}{8}-\dfrac{1}{9}\)

`=`\(\dfrac{4}{10}-\dfrac{11}{3}+\dfrac{7}{8}-\dfrac{1}{9}\)

`=`\(-\dfrac{49}{15}+\dfrac{7}{8}-\dfrac{1}{9}\)

`=`\(-\dfrac{287}{120}-\dfrac{1}{9}=-\dfrac{901}{360}\)

`i )`

\(3\cdot\dfrac{1}{5}-\dfrac{2}{8}-\dfrac{12}{36}+\dfrac{15}{9}\)

`=`\(\dfrac{3}{5}-\dfrac{1}{4}-\dfrac{1}{3}+\dfrac{15}{9}\)

`=`\(\dfrac{7}{20}-\dfrac{1}{3}+\dfrac{15}{9}\)

`=`\(\dfrac{1}{60}+\dfrac{15}{9}=-\dfrac{33}{20}\)

`k)`

\(\dfrac{6}{8}\cdot3\dfrac{1}{2}+4\dfrac{2}{3}-\dfrac{11}{55}+\dfrac{17}{51}\)

`=`\(\dfrac{3}{4}\cdot\dfrac{7}{2}+\dfrac{14}{3}-\dfrac{1}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{21}{8}+\dfrac{14}{3}-\dfrac{1}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{175}{24}-\dfrac{1}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{851}{120}+\dfrac{17}{51}=\dfrac{297}{40}\)

`l )`

\(\dfrac{1}{3}\cdot3\dfrac{1}{2}-4\dfrac{2}{5}-\dfrac{26}{78}+\dfrac{17}{51}\)

`=`\(\dfrac{1}{3}\cdot\dfrac{7}{2}-\dfrac{22}{5}-\dfrac{1}{3}+\dfrac{17}{51}\)

`=`\(\dfrac{1}{3}\left(\dfrac{7}{2}-1\right)-\dfrac{22}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{1}{3}\cdot\dfrac{5}{2}-\dfrac{22}{5}+\dfrac{17}{51}\)

`=`\(\dfrac{5}{6}-\dfrac{22}{5}+\dfrac{17}{51}\)

`=`\(-\dfrac{107}{30}+\dfrac{17}{51}=-\dfrac{97}{30}\)

P/s: Bạn tách bài ra hỏi nhé! Và ghi đề rõ ràng chứ đừng ghi ntnay, nhiều bạn nhìn vào rất khó nhìn!

`# \text {KaizulvG}`

a) 

`  1/2 - 5/6 + 11/33 - 35/40 `

`= 1/2 - 5/6 + 1/3 - 7/8 `

`= ( 1/2 - 5/6 ) + ( 1/3 - 7/8 ) `

`= ( 3/6 - 5/6 ) + ( 8/24 - 21/24 ) `

`= -2/6 + (-13)/24 `

`= -1/3 + (-13)/24 `

`= -8/24 + (-13)/24 `

`= -21/24 = -7/8 `