The parent chain and the numbers are marked in red on the image.
Work Step by Step
1. Find the parent chain. In this case, the rules are: - It has to be as large as possible. - It has to contain the double bond. 2. Identify where you are supposed to start counting. The counting should start from the right, since the double bond is closer to the right side. ** We need to count in a way that, the insaturation gets the minimum number possible, which we do by starting from the right.