Question

Tính:

3/7 + 4 = .............................................

5/9 x 3 = .............................................

7/8 - 2/9 = ..........................................

5 - 3/4 = .............................................

5/7 : 6 = .............................................

5/6 x 2/7 = .........................................

3 + 3/4 = ...........................................

3/5 x 4/8 = ........................................

5 : 3/8 = ............................................

3 x 5/9 = ...........................................

Answer 1

3/7 + 4 = 3/7 + 4/1 = 31/7

5/9 x 3 =5/9 x 3/1 = 15/9 = 5/3

7/8 - 2/9 =7/8 - 2/9 =47/72

5 - 3/4 =5/1 - 3/4 = 20/4 - 3/4 = 17/4

5/7 : 6 = 5/7 : 6/1 = 5/7 x 1/6 = 5/42

5/6 x 2/7 =10/42= 5/21

3 + 3/4 = 3/1 + 3/4 = 12/4+ 3/4 =15/4

3/5 x 4/8 =12/40 = 3/10.

5 : 3/8 = 5/1 : 3/8 = 5/1 x 8/5 = 8/1= 8

3 x 5/9 =3/1 x 5/9 = 15/9=5/3

 

Answer 2

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

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

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

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

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

l) \(3\times\dfrac{5}{9}=\dfrac{3\times5}{9}=\dfrac{15}{9}=\dfrac{5}{3}\)