Răspuns :
a ) 1 / 3 + 1 / 6 =
= ( 2 + 1 ) / 6
= 3 / 6
= 1 / 2
---------------------------
b ) 3 / 10 + 1 / 5 + 3 / 2 =
= ( 3 + 2 + 15 ) / 10
= ( 5 + 15 ) / 10
= 20 / 10
= 2
----------------------------
c ) 7 / 12 + 3 / 4 =
= ( 7 + 9 ) / 12
= 16 / 12
= 4 / 3
--------------------------
d ) 7 / 20 + 3 / 4 + 1 / 5 =
= ( 7 + 15 + 4 ) / 20
= ( 22 + 4 ) / 20
= 26 / 20
= 13 / 10