= 51/20

----------------------------------

= 3/14

------------------------------------

= 4/7 - 2/7 

= 2/7

--------------------------------------

= 17/45

---------------------------------------

= 2/3 

--------------------------------------

= 2 x 1/4 

= 1/2

9/7*(4/5+1/5)-2/7*(1/6+5/6)=

9/7*1-2/7*1=

9/7-2/7=

=1

Ta có:

a) ( 45 – 5 x 9 ) x 1 x 2 x 3 x 4 x 5 x 6 x 7

= (45 – 45) x 1 x 2 x 3 x 4 x 5 x 6 x 7

= 0 x 1 x 2 x 3 x 4 x 5 x 6 x 7

= 0

b) (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 8 x 8 – 8)

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 64 – 8)

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x 0

= 0

c) (36 – 4 x 9) : (3 x 5 x 7 x 9 x 11)

= (36 – 36) : (3 x 5 x 7 x 9 x 11)

= 0 : (3 x 5 x 7 x 9 x 11)

= 0

d) (27 – 3 x 9) : 9 x 1 x 3 x 5 x 7

= (27 – 27) : 9 x 1 x 3 x 5 x 7

= 0 : 9 x 1 x 3 x 5 x 7

=0

a) ( 45 – 5 x 9 ) x 1 x 2 x 3 x 4 x 5 x 6 x 7

= 0 x 1 x 2 x 3 x 4 x 5 x 6 x 7

b) (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x (72 – 8 x 8 – 8)

= (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) x 0

c) (36 – 4 x 9) : (3 x 5 x 7 x 9 x 11)

= 0 : (3 x 5 x 7 x 9 x 11)

d) (27 – 3 x 9) : 9 x 1 x 3 x 5 x 7

= 0 : 9 x 1 x 3 x 5 x 7                                                                                                                  Nếu đúng thì k cho mình nhé bạn!

215

215

a) \(\dfrac{3}{7}+4=\dfrac{3}{7}+\dfrac{4}{1}=\dfrac{3}{7}+\dfrac{28}{7}=\dfrac{31}{7}\)

b) \(\dfrac{5}{9}\times3=\dfrac{5\times3}{9}=\dfrac{15}{9}=\dfrac{5}{3}\)

c) \(\dfrac{7}{8}-\dfrac{2}{9}=\dfrac{63}{72}-\dfrac{16}{72}=\dfrac{47}{72}\)

d) \(5-\dfrac{3}{4}=\dfrac{5}{1}-\dfrac{3}{4}=\dfrac{20}{4}-\dfrac{3}{4}=\dfrac{17}{4}\)

e) \(\dfrac{5}{7}:6=\dfrac{5}{7}:\dfrac{6}{1}=\dfrac{5}{7}\times\dfrac{1}{6}=\dfrac{5}{42}\)

f) \(\dfrac{5}{6}\times\dfrac{2}{7}=\dfrac{5\times2}{6\times7}=\dfrac{10}{42}=\dfrac{5}{21}\)

g) \(3+\dfrac{3}{4}=\dfrac{3}{1}+\dfrac{3}{4}=\dfrac{12}{4}+\dfrac{3}{4}=\dfrac{15}{4}\)

h) \(\dfrac{3}{5}\times\dfrac{4}{8}=\dfrac{3\times4}{5\times8}=\dfrac{12}{40}=\dfrac{3}{10}\)

i) \(5:\dfrac{3}{8}=\dfrac{5}{1}:\dfrac{3}{8}=\dfrac{5}{1}\times\dfrac{8}{3}=\dfrac{40}{3}\)

\(\dfrac{3}{7}+\dfrac{4}{1}=\dfrac{3}{7}+\dfrac{28}{7}=\dfrac{31}{7}\)

\(\dfrac{5}{9}\times3=\dfrac{5}{9}\times\dfrac{3}{1}=\dfrac{15}{9}=\dfrac{5}{3}\)

\(\dfrac{7}{8}-\dfrac{2}{9}=\dfrac{63}{72}-\dfrac{16}{72}=\dfrac{47}{72}\)

\(\dfrac{5}{1}-\dfrac{3}{4}=\dfrac{20}{4}-\dfrac{3}{4}=\dfrac{17}{4}\)

\(\dfrac{5}{7}:\dfrac{6}{1}=\dfrac{5}{7}\times\dfrac{1}{6}=\dfrac{5}{42}\)

\(\dfrac{5}{6}\times\dfrac{2}{7}=\dfrac{5\times2}{6\times7}=\dfrac{10}{42}=\dfrac{5}{21}\)

\(\dfrac{3}{1}+\dfrac{3}{4}=\dfrac{12}{4}+\dfrac{3}{4}=\dfrac{15}{4}\)

\(\dfrac{3}{5}\times\dfrac{4}{8}=\dfrac{3}{5}\times\dfrac{1}{2}=\dfrac{3\times1}{5\times2}=\dfrac{3}{10}\)

\(\dfrac{5}{1}:\dfrac{3}{8}=\dfrac{5}{1}\times\dfrac{8}{3}=\dfrac{40}{3}\)

a) 4 + 5/7 = .... 28/7 + 5/7=.33/7..............

    5/9 x 6/7 = ..10/21....

    3 - 7/5 =  15/5 - 7/5...8/5........

    3/5 x 4/8 = ..3/10....

b) 2 - 1/4 = .8/4 - 1/4...7/4...

    4 : 5/9 = ..4 x 9/5 = 36/5....

    2/9 x 3/5 = .....2/15.....

    3/8 : 4 = ......3/8 x 1/4 = 3/2.....

Thanks kiuuuuuuu

2 năm sau mày sẽ chết do dịch bệnh

Bài 2:

a: 2/6x5/3=10/18=5/9

b: 11/9x5/10=55/90=11/18

c: 3/9x6/8=1/3x3/4=1/4

d: 4/9x12/16=48/144=1/3

e: 25/15x6/7=5/3x6/7=30/21=10/7

f: 6/10x15/20=90/200=9/20

Bài 1

4/5 x 6/7= 24/35

2/9 x 1/2= 2/18= 1/9

1/2 x 8/3= 8/6= 4/3

7/9 x 6/5= 42/45= 14/15

8/7 x 5/9= 40/63

10/11 x 22/15= 220/165= 4/3

Bài 2

2/6 x 5/3= 1/3 x 5/3=5/9

11/9 x 5/10= 11/9 x 1/2= 11/18

3/9 x 6/8= 1/3 x 3/4 =3/12= 1/4

4/9 x 12/16= 4/9 x 3/4= 12/36= 1/3

25/15 x 6/7= 5/3 x 6/7= 30/21= 10/7

6/10 x 15/20= 3/5 x 3/4= 9/20

a/=4/9x10/3=40/27

b/=15/49

c/=4/9x2/3=8/27

a)\(=\dfrac{4}{9}\times\dfrac{10}{3}=\dfrac{40}{27}\)

b)\(\dfrac{3}{7}\times\dfrac{5}{7}=\dfrac{15}{49}\)

c)\(\dfrac{4}{9}:\dfrac{3}{2}=\dfrac{4}{9}\times\dfrac{2}{3}=\dfrac{8}{27}\)