Question

(7/9 + 77/99 + 777/999) ori 1/3

Answer 1

$( \frac{7}{9} + \frac{77}{99} + \frac{777}{999}) \times \frac{1}{3} = ( \frac{7}{9} + \frac{7}{9} + \frac{7}{9}) \times \frac{1}{3} = \frac{21}{9} \times \frac{1}{3} = \frac{7}{3} \times \frac{1}{3} = \frac{7 \times 1}{3 \times 3} = \frac{7}{9}$

Answer 2

( 7 / 9 + 77 / 99 + 777 / 999 ) x 1 / 3 =

= [ ( 7 / 9 ) x ( 1 / 1 ) + ( 7 / 9 ) x ( 11 / 11 ) + ( 7 / 9 ) x ( 111 / 111) ] x 1 / 3 =

→ dau factor comun pe 7 / 9

= 7 / 9 x ( 1 / 1 + 11 / 11 + 111 / 111 ) x 1 / 3 =

= ( 7 / 9 ) x ( 1 + 1 + 1 ) x 1 / 3 =

= 7 / 9 x 3 x 1 / 3 =

= 7 / 9