STEREOCHEMISTRY of E/Z alkene?

Question

How could the olefinic stereochemistry ( E or Z) be deduced?

thanks a lot ..........

Answer 1

E stands for trans and Z for cis
1st decide priority of gps on 1st C atom then on 2nd C atom
if the high priority gps on each carbon are on same side then it is Z & if on opposite they are E

priority is decided by

CH3 or by atomic no one having high at no is given high priority