Question

Tính bằng cách thuận tiện:

9/5 + 4/7 + 6/5 + 3/7 = .........................................................

1/2 x 45/33 x 1/9 x 11/6 = ....................................................

Answer 1

9/5 + 4/7 + 6/5 + 3/7

=  ( 9/5 + 6/5 ) + ( 4/7 + 3/7)

=            3        + 1

=        4

 

Answer 2

9/5 + 4/7 + 6/5 + 3/7 = (9/5 + 6/5) + (4/7 + 3/7)

= 15/5 + 7/7

= 3 + 1

= 4

1/2 x 45/33 x 1/9 x 11/6 = (1/2 x 1/9) x (45/33 x 11/6)

= 1/18 x 45/18

= 5/2

Answer 3

1/2 x 45/33 x 1/9 x 11/6

= (1/2 x 1/9) x (45/33 x 11/6)

= 1/18 x 45/18

= 5/2

Answer 4

9/5 + 4/7 + 6/5 + 3/7 = (9/5 + 6/5) + (4/7 + 3/7)

= 15/5 + 7/7

= 3 + 1

= 4

1/2 x 45/33 x 1/9 x 11/6 = (1/2 x 1/9) x (45/33 x 11/6)

= 1/18 x 45/18

= 5/2

Answer 5

a) \(\dfrac{9}{5}+\dfrac{4}{7}+\dfrac{6}{5}+\dfrac{3}{7}=\left(\dfrac{9}{5}+\dfrac{6}{5}\right)+\left(\dfrac{4}{7}+\dfrac{3}{7}\right)=\dfrac{15}{5}+\dfrac{7}{7}=3+1=4\)

b) \(\dfrac{1}{2}\times\dfrac{45}{33}\times\dfrac{1}{9}\times\dfrac{11}{6}=\dfrac{11}{11}\times\dfrac{15}{6}\times\dfrac{1}{18}=1\times\dfrac{15}{6}\times\dfrac{1}{8}=1\times\dfrac{5}{2}\times\dfrac{1}{18}=\dfrac{5}{2}\times\dfrac{1}{18}=\dfrac{5}{36}\)

Answer 6

1/2 x 45/33 x 1/9 x 11/6

= (1/2 x 1/9) x (45/33 x 11/6)

= 1/18 x 45/18

= 5/2

Answer 7

9/5 + 4/7 + 6/5 + 3/7

=  ( 9/5 + 6/5 ) + ( 4/7 + 3/7)

=            3        + 1

=        4

1/2 x 45/33 x 1/9 x 11/6 = (1/2 x 1/9) x (45/33 x 11/6)

= 1/18 x 45/18

= 5/2