a, 13/6+5/8 : -3/4 - 7/12.4

= 13/6 + -5/6-7/3

=8/6-7/3

= -6/6

= -1

b, ( 73/5 - 21/3) + ( 4/3-43/5 )

= 73/5-21/3+4/3-43/5

=( 73/5-43/5)-(21/3-4/3)

= 6-17/3

=1/3

c, 7/5.4/9 +7/5: 9/16- 14/10.2/9

= 7/5.4/9 +7/5.16/9 - 14/45

=7/5.(4/9+16/9)-14/45

=7/5.20/9-14/45

= 140/45 - 14/45

= 126/45

Xong rùi nè! Nhưng bạn kiểm tra lại giùm nhé vì làm vào ban đêm nên hơi bất tiện

Trời ạ. 7 3/5 chứ k phải 73/5 -_-

ghi rõ thêm từ và nhé!

Xóa nhanh đi ko CTV xóa giờ

Chia chúng nó ra

Câu dễ vậy bạn cần hỏi

1: =72/90+65/90=137/90

2: =24/56-77/56=-53/56

3: =-7/10+4/5=1/10

4: =15/100-4/100=11/100

5: =4/6-5/6=-1/6

6: =10/40-15/40-76/40=-81/40

7: =-9/10+7/18

=-81/90+35/90=-46/90=-23/45

8: =27/90-55/90=-28/90=-14/45

9: =36/60-50/60-35/60=-49/60

10: =-4/9+5/6-3/8

=-32/72+60/72-27/72

=1/72

\(1,\dfrac{4}{5}+\dfrac{13}{18}=\dfrac{72}{90}+\dfrac{65}{90}=\dfrac{137}{90}\)

\(2,\dfrac{3}{7}-\dfrac{11}{8}=\dfrac{24}{56}-\dfrac{77}{56}=\dfrac{-53}{56}\)

\(3,-\dfrac{7}{10}-\left(-\dfrac{4}{5}\right)=-\dfrac{7}{10}-\left(-\dfrac{8}{10}\right)=\dfrac{1}{10}\)

\(4,\dfrac{3}{20}-\dfrac{1}{25}=\dfrac{75}{500}-\dfrac{20}{500}=\dfrac{55}{500}=\dfrac{11}{100}\)

\(5,\dfrac{2}{3}-\dfrac{5}{6}=\dfrac{12}{18}-\dfrac{15}{18}=-\dfrac{3}{18}=-\dfrac{1}{6}\)

\(6,\dfrac{1}{4}+\left(-\dfrac{3}{8}\right)-\dfrac{19}{10}=\dfrac{8}{32}+\left(-\dfrac{12}{32}\right)-\dfrac{19}{10}=-\dfrac{4}{32}-\dfrac{19}{10}\)

\(=-\dfrac{1}{8}-\dfrac{19}{10}=-\dfrac{10}{80}-\dfrac{152}{80}=-\dfrac{162}{80}=-\dfrac{81}{40}\)

\(7,-\dfrac{9}{10}-\left(-\dfrac{7}{18}\right)=-\dfrac{162}{180}-\left(-\dfrac{70}{180}\right)=-\dfrac{92}{180}=-\dfrac{23}{45}\)

\(8,\dfrac{3}{10}-\dfrac{11}{18}=\dfrac{54}{180}-\dfrac{110}{180}=-\dfrac{56}{180}=-\dfrac{14}{45}\)

\(9,\dfrac{3}{5}-\dfrac{5}{6}+\left(-\dfrac{7}{12}\right)=\dfrac{18}{30}-\dfrac{25}{30}+\left(-\dfrac{7}{12}\right)=-\dfrac{7}{30}+\left(-\dfrac{7}{12}\right)\)

\(=-\dfrac{84}{360}+\left(-\dfrac{210}{360}\right)=-\dfrac{294}{360}=-\dfrac{49}{60}\)

\(10,-\dfrac{4}{9}-\dfrac{-5}{6}-\dfrac{3}{8}=-\dfrac{24}{54}-\dfrac{-45}{54}-\dfrac{3}{8}\)

\(=\dfrac{21}{54}-\dfrac{3}{8}=\dfrac{7}{18}-\dfrac{3}{8}=\dfrac{56}{144}-\dfrac{54}{144}=\dfrac{2}{144}=\dfrac{1}{72}\)

`@mt`

Câu 11: B

Câu 12: B

Câu 13: A

Câu 14: C

Câu 15: D

tui ko biÕt

B=1+2-3-4+5+6-7-8+...+197+198-198-200

B=(1+2-3-4)+(5+6-7-8+9)+...+(197+198-198-200)

B=-4+(-4)+.....+(-4)

B=(-4)x50

B=-200

câu A bạn ghép 4 số đầu lại có kết quả là -8x325=-2600            ^-^

bây giờ như thế này nhá, bạn xem thằng TRÍ đi

Đề yêu cầu gì vậy em?

đây là so sánh hay quy đồng v 

\(\dfrac{3}{5}v\text{à}\dfrac{7}{3}\\ MSC:15\\ \dfrac{3}{5}=\dfrac{3\times3}{5\times3}=\dfrac{9}{15};\dfrac{7}{3}=\dfrac{7\times5}{5\times3}=\dfrac{35}{15}\\ 9< 35\\ \Rightarrow\dfrac{3}{5}< \dfrac{7}{5}\\ \dfrac{9}{10}v\text{à}\dfrac{5}{4}\\MSC:20\\ \dfrac{9\times2}{10\times2}=\dfrac{18}{20};\dfrac{5}{4}=\dfrac{5\times5}{4\times5}=\dfrac{25}{20}\\ 18< 25\\ \Rightarrow\dfrac{9}{10}< \dfrac{5}{4}\\ \dfrac{2}{7}v\text{à}\dfrac{5}{4}\\ MSC:28\\ \dfrac{2}{7}=\dfrac{2\times4}{7\times4}=\dfrac{8}{28};\dfrac{5}{4}=\dfrac{5\times7}{4\times7}=\dfrac{35}{28}\\ 8< 35\\ \dfrac{2}{7}< \dfrac{5}{4}\\ \dfrac{8}{9}v\text{à}\dfrac{11}{6}\\ MSC:18\\ \dfrac{8\times2}{9\times2}=\dfrac{16}{18};\dfrac{11}{6}=\dfrac{11\times3}{6\times3}=\dfrac{33}{18}\\ 16< 33\\ \Rightarrow\dfrac{8}{9}< \dfrac{11}{6}\)

Quy đồng hả ?

\(\dfrac{3}{5}và\dfrac{7}{3}=\dfrac{3}{5}=\dfrac{3\times3}{5\times3}=\dfrac{9}{15};\dfrac{7}{3}=\dfrac{7\times5}{3\times5}=\dfrac{35}{15}\)

\(\dfrac{9}{10}và\dfrac{5}{4}=\dfrac{9}{10}=\dfrac{9\times2}{10\times2}=\dfrac{18}{20};\dfrac{5}{4}=\dfrac{5\times5}{4\times5}=\dfrac{25}{20}\)

\(\dfrac{2}{7}và\dfrac{5}{4}=\dfrac{2}{7}=\dfrac{2\times4}{7\times4}=\dfrac{8}{28};\dfrac{5}{4}=\dfrac{5\times7}{4\times7}=\dfrac{35}{28}\)

\(\dfrac{8}{9}và\dfrac{11}{6}=\dfrac{8}{9}=\dfrac{8\times2}{9\times2}=\dfrac{16}{18};\dfrac{11}{6}=\dfrac{11\times3}{6\times3}=\dfrac{33}{18}\)

\(\dfrac{6}{5}và\dfrac{13}{8}=\dfrac{6\times8}{5\times8}=\dfrac{48}{40};\dfrac{13}{8}=\dfrac{13\times5}{8\times5}=\dfrac{65}{40}\)

\(\dfrac{4}{5}và\dfrac{3}{2}=\dfrac{4}{5}=\dfrac{4\times2}{5\times2}=\dfrac{8}{10};\dfrac{3}{2}=\dfrac{3\times5}{2\times5}=\dfrac{15}{10}\)

\(\dfrac{5}{12}và\dfrac{7}{8}=\dfrac{5}{12}=\dfrac{5\times2}{12\times2}=\dfrac{10}{24};\dfrac{7}{8}=\dfrac{7\times3}{8\times3}=\dfrac{21}{24}\)

\(\dfrac{11}{4}và\dfrac{13}{6}=\dfrac{11}{4}=\dfrac{11\times3}{4\times3}=\dfrac{33}{12};\dfrac{13}{6}=\dfrac{13\times2}{6\times2}=\dfrac{26}{12}\)

a) \(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+........+\frac{1}{99.100}\)

\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+.........+\frac{1}{99}-\frac{1}{100}\)

\(=\frac{1}{2}-\frac{1}{100}=\frac{49}{100}\)

b) \(\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+..........+\frac{2}{73.75}\)

\(=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+.......+\frac{1}{73}-\frac{1}{75}\)

\(=\frac{1}{3}-\frac{1}{75}=\frac{8}{25}\)

c) \(\frac{4}{4.6}+\frac{4}{6.8}+\frac{4}{8.10}+..........+\frac{4}{64.66}\)

\(=2.\left(\frac{2}{4.6}+\frac{2}{6.8}+\frac{2}{8.10}+..........+\frac{2}{64.66}\right)\)

\(=2.\left(\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+\frac{1}{8}-\frac{1}{10}+.....+\frac{1}{64}-\frac{1}{66}\right)\)

\(=2.\left(\frac{1}{4}-\frac{1}{66}\right)=2.\frac{31}{132}=\frac{31}{66}\)

d) \(\frac{9}{5.8}+\frac{9}{8.11}+\frac{9}{11.14}+........+\frac{9}{497.500}\)

\(=3.\left(\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}+..........+\frac{3}{497.500}\right)\)

\(=3.\left(\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+......+\frac{1}{497}-\frac{1}{500}\right)\)

\(=3.\left(\frac{1}{5}-\frac{1}{500}\right)=3.\frac{99}{500}=\frac{297}{500}\)

e) \(\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}+......+\frac{1}{93.95}\)

\(=\frac{1}{2}.\left(\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+........+\frac{2}{93.95}\right)\)

\(=\frac{1}{2}.\left(\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+........+\frac{1}{93}-\frac{1}{95}\right)\)

\(=\frac{1}{2}.\left(\frac{1}{5}-\frac{1}{95}\right)=\frac{1}{2}.\frac{18}{95}=\frac{9}{95}\)

g) \(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+..........+\frac{1}{200.203}\)

\(=\frac{1}{3}.\left(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+........+\frac{3}{200.203}\right)\)

\(=\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+......+\frac{1}{200}-\frac{1}{203}\right)\)

\(=\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{203}\right)=\frac{1}{3}.\frac{201}{406}=\frac{67}{406}\)

bạn juventus ơi , bạn làm nốt cho mình mấy câu sau với