Question

Answer 1

a, 8 + 21/5

 =  8/1 + 21/5

=   40/5 + 21/5

 =   61/5

 

b,21/15-4/3

=  21/15 - 20/15

=  1/15

Answer 2

a.\(8+\dfrac{21}{5}=\dfrac{61}{5}\)
\(\dfrac{21}{15}-\dfrac{4}{3}=\dfrac{21}{15}-\dfrac{20}{15}=\dfrac{1}{15}\)
c.\(12:\dfrac{27}{45}=12:\dfrac{3}{5}=20\)
d.\(\dfrac{1}{5}:\dfrac{1}{3}x\dfrac{4}{5}=\dfrac{12}{25}\)
e.\(\dfrac{3}{17}x24=\dfrac{72}{17}\)
 

Answer 3

 8 + 21/5 =  8/1 + 21/5=   40/5 + 21/5 =   61/5

 

21/15 - 4/3=  21/15 - 20/15=  1/15

Answer 4

a, Lời giải :

Tham khảo :

 =  \(8+\dfrac{21}{5}\)

 =  \(\dfrac{8}{1}+\dfrac{21}{5}\)

=   \(\dfrac{40}{5}+\dfrac{21}{5}\)

 =   \(\dfrac{61}{5}\)

 

b, Lời giải : 

Tham khảo :

=  \(\dfrac{21}{15}-\dfrac{4}{3}\)

=  \(\dfrac{21}{15}-\dfrac{20}{15}\)

=  \(\dfrac{1}{15}\)

Answer 5

a) \(8+\dfrac{21}{5}=\dfrac{8}{1}+\dfrac{21}{5}=\dfrac{40}{5}+\dfrac{21}{5}=\dfrac{61}{6}\)

b) \(\dfrac{21}{15}-\dfrac{4}{3}=\dfrac{21}{15}-\dfrac{20}{15}=\dfrac{1}{15}\)

c) \(12:\dfrac{27}{45}=12:\dfrac{3}{5}=20\)

d) \(\dfrac{1}{5}:\dfrac{1}{3}\) x \(\dfrac{4}{5}=\dfrac{12}{25}\)

e) \(\dfrac{3}{17}\) x \(24=\dfrac{3}{17}\) x \(\dfrac{24}{1}=\dfrac{72}{17}\)