Do I subtract, add then divide by 2 ?

We need to first find m< AOE

This equals

180 - m<BOA - m<EOD =

180 - 40 - 60  = 80

And notice that < COD is a vertical angle = <BOE

And m<BOE = m<BOA + m<AOE = 40 + 80 = 120 = m<COD

what about EOB? that woud be parallel?

Parallel to what???  EOB is an angle.