You are planning a wedding, and there are 10 people participating in the wedding ceremony.

During the ceremony, the 10 participants will walk down the aisle in pairs (groups of 2), one pair at a time. How many ways can the 10 participants walk down the aisle in pairs if it matters which person is on the left of the aisle, and which is on the right?

After walking down the aisle and completing the wedding ceremony, the 10 participants will leave the ceremony in pairs. How many ways can the 10 participants leave the ceremony in pairs, one pair at a time, if the left and right orientation of each pair is now irrelevant?

After leaving the ceremony there is a reception held where the 10 wedding participants will dance together. How many ways can the 10 participants form pairs while dancing at the same time?