Amplificam fiecare fractie pentru a o aduce la numitor comun, deci:
a) 1/18+ 1/9+ 1/6=
=1/18+ 2/18+ 3/18=
=6/18=
=1/3
b) 7/36- 1/18+ 3/4=
=7/36- 2/36+ 27/36=
=32/36=
=8/9
c) 37/18- 3/4- 5/6=
=74/36- 27/36- 30/36=
=17/36
d) 11/18- 4/9+ 5/6- 1/3=
=11/18- 8/18+ 15/18- 6/18=
=12/18=
=2/3