Question

1  0,5×(1 supra 3+1 supra 3² -0,1(6) )
 2   1 supra 2004 -1 supra 2004×2005-1 supra 2005×2006
3     (1 supra 2+ 5 supra 6 -3 supra 4 ) :7 supra 300

Answer 1

1)...    0,5(1/3+1/9-1/6)=1/2 * [(6+2-3):(18)]=1/2 * 5/18 = 5 / 36 ;

2)...    1 / 2004 - (1 / 2004 - 1 / 2005) - (1 / 2005 - 1 / 2006) =
          = 1/2004 -1/2004+1/2005+1/2005+1/2006 = 1 / 2006 ;

3)...   (1/2 + 5/6 - 3/4 ):7/300=[ (6+10-9) / 12] * 300 / 7 =
          =7 / 12 * 300 / 7 =300 :12 = 25 ;