\(\frac{5}{27}+\frac{3}{4}+\frac{22}{27}+\frac{1}{4}\)

\(=\left(\frac{5}{27}+\frac{22}{27}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)\)

\(=1+1\)

\(=2\)

\(\frac{89}{92}-\frac{30}{92}-\frac{59}{92}\)

\(=\frac{89-30-59}{92}\)

\(=\frac{59-59}{92}\)

\(=\frac{0}{92}\)

\(=0\)

bài 2 đề sai rồi

bạn xem lại nhé

\(\frac{1}{2}+\frac{5}{6}+\frac{11}{12}+\frac{19}{20}+...+\frac{89}{90}\)

\(=1-\frac{1}{2}+1-\frac{1}{6}+1-\frac{1}{12}+1-\frac{1}{20}+...+1-\frac{1}{90}\)

\(=9-\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{90}\right)\)

\(=9-\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{9.10}\right)\)

\(=9-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{9}-\frac{1}{10}\right)\)

\(=9-\left(1-\frac{1}{10}\right)\)

\(=9-\frac{9}{10}=\frac{81}{10}\)

58 + 92 -73:11

=58 + 92 -73/11

=150-73/11

=1577/11

25+72:(24+1)+72

=25+72:25+72

=25+2,88+72

=27,88+72

=99,88

\(=150-\frac{73}{11}=\frac{1577}{11}\)

\(=25+72:25+72=25+72:\left(25+1\right)=25+72:26=25+3=28\)

Số các số hạng là

  ( 92 - 5 ) :3 + 1 = 30 ( só hạng )

Tổng  của dãy số trên là

 ( 92 + 5 ) . 30 : 2 = 1455

           Đáp số : 1455

Có Số số hạng là:(92-5):3+1=30(số)

Tổng là:(92+5)*30:2=1455

Số số hạng là : ( 92 - 5 ) : 3 + 1 = 30 ( số hạng )

Tổng : 5 + 8 + 11 + 14 + ... + 89 + 92

= ( 92 + 5 ) x 30 : 2

= 97 x 30 : 2

= 2910 : 2

= 1455

A. 1155 nha bạn 

Ta có :

\(\frac{5}{9}\times\frac{2}{7}=\frac{10}{63};\frac{2}{3}+\frac{5}{6}=\frac{3}{2}\)               \(5-\frac{13}{17}=\frac{72}{17};\frac{9}{11}:\frac{5}{13}=\frac{117}{55}\)

\(5+\frac{9}{14}=\frac{79}{14};\frac{6}{54}:8=\frac{1}{72}\)               \(\frac{24}{72}-\frac{202}{909}=\frac{1}{9};\frac{9}{11}:\frac{5}{13}=\frac{117}{55}\)

Học tốt nha !

#Sơn#

5/9\(\times\)2/7=10/63

2/3+5/6=4/6+5/6=9/6=3/2

5+9/14=70/14+9/14=79/14

6/54:8=1/9:8=1/9\(\times\)1/8=1/72

5-13/17=85/17-13/17=72/17

3:9/10=3\(\times\)10/9=30/9=10/3

24/72-202/909=1/9

9/11:5/13=9/11\(\times\)13/5=117/55

\(\frac{5}{9}\)\(\times\frac{2}{7}\)\(=\frac{5\times2}{9\times7}\)\(=\frac{10}{63}\)

\(\frac{2}{3}\)\(+\frac{5}{6}\)\(=\frac{12+15}{18}\)\(=\frac{27}{18}\)\(=\frac{3}{2}\)

\(5+\frac{9}{14}\)\(=\frac{70+9}{14}\)\(=\frac{79}{14}\)

\(\frac{6}{54}\)\(\div8\)\(=\frac{6}{54}\)\(\times\frac{1}{8}\)\(=\frac{6\times1}{54\times8}\)\(=\frac{6}{432}\)\(=\frac{1}{72}\)

\(5-\frac{13}{17}\)\(=\frac{85-13}{17}\)\(=\frac{72}{17}\)

\(3\div\frac{9}{10}\)\(=3\times\frac{10}{9}\)\(=\frac{3\times10}{9}\)\(=\frac{30}{9}\)\(=\frac{10}{3}\)

\(\frac{24}{72}\)\(-\frac{202}{909}\)\(=\frac{21816-14544}{65448}\)\(=\frac{7272}{65448}\)\(=\frac{1}{9}\)

\(\frac{9}{11}\)\(\div\frac{5}{13}\)\(=\frac{9}{11}\)\(\times\frac{13}{5}\)\(=\frac{9\times13}{11\times5}\)\(=\frac{117}{55}\)

Hok tốt !

Bài 2:

a. $=62-81-12+59-9=(62-12)+(59-9)-81$

$=50+50-81=100-81=19$

b. $=39+13-26-62-39=(39-39)+13-(26+62)$

$=0+13-88=-(88-13)=-75$

c. $=(32-42)+(36-34)+(40-38)=10+2+2=14$
d. $=92-55+8-45=(92+8)-(55+45)=100-100=0$

Bài 1:

a. $=(387-87)-224=300-224=76$

b. $=-(75+35)+379=-110+379=379-110=269$

c. $=(11+15)-(13+17)=25-30=-5$

d. $=(31-21)-(27-24)=10-3=7$

Tính nhanh các tổng sau:           

a) 2 + 5 + 8 + 11 + 14 + 17 + 20 + 23 + 26 + 29         

= ( 2+ 8 ) + ( 5 + 20) + ( 11 + 29 ) + ( 14 + 26 ) + ( 17 + 23 )           

=    10     +    25       +    40          +     40        +      40         

=              35           +          120            

=    155                           

b) 120 + 116 + 112 + 108 + 104 + 100 + 96 + 92 + 88 + 84 + 80             

= ( 120 + 80 ) + ( 116 + 84 )+ ( 112 + 88 ) + ( 108 + 92 ) + ( 104 + 96 ) + 100              

=      200       +      200        +       200       +      200        +       200      +  100          

= 200 x 5 + 100           

= 1100

a, So so hang la

( 29 - 2 ) : 3 + 1 = 10 ( so )

Tong la : ( 29 + 2 ) x 10 : 2 = 155

b,So so hang la

( 120 - 80 ) : 4 + 1 = 11 ( so )

Tong la

( 120 + 80 ) x 11 : 2 = 1100

a) ( 2 + 29 ) + ( 5 + 26 ) + ( 8 + 23 ) + ( 11 + 20 ) + ( 14 + 17 )

= 31 + 31 + 31 + 31 + 31

= 31 x 5

= 155

b) ( 120 + 80 ) + ( 116 + 84 ) + ( 112 + 88 ) + ( 108 + 92 ) + ( 104 + 96 ) + 100

=    200          +    200          +      200        +    200          +    200         + 100

= 200 x 5 + 100

= 110

k mình nhé mấy bạn