1. deoarece au acelasi numitor
a=(101-73+47)/210=75/210=15/42
2 SI 3
X=1/16:1/16=1
X-1/X=1-1=0
4. (4.63)/(21.20)=252/420=126/210=63/105
5. 576/100x(-100/24): (-33/5)=-24:(-33/5)=792/5
6. 7/3=1/3 +2
9/4=1/4+2
atunci sirul devine
1/3+2-1/4-2+1/5+2-.................+1/1007+2=
in sir se reduce 2⇒
(1/3-1/4+1/5-.............+1/1007+2)-(1/3-1/4+.......................+1/1007)=2-1=1