Răspuns :

2a = 1 6/9 + 3/9 => 2a = 18/9 => a = 1 => b = 1 - 3/9 => b = 6/9 = 2/3 = 0,(6)
a+b=16-10/90=6/90=2/30=1/15
a-b=3/9=1/3
 le aduni si da 2a=1/15+1/3
amplifici si da 2a=(1+5)/15
2a=6/15 adica 2a=2/5==> a=(2/5)2 adica a=2/10=1/5