I want to change the numbers of my partitons. I want to change /dev/sda1 into /dev/sda5 and /dev/sda5 into /dev/sda1. I hope someone can help me to change it. Thanks :)
You can't change them you'd have to move the partitions around.
You can only have 4 primary partitions so:
Devices are named by their placement in the partition table of the disk ex:
sda1 is the first primary partition sda2 is the second primary partition sda3 is the third primary partition sda4 is the fourth primary partition
Extended partition will take up a space on the primary partition table for the extended container like /dev/sda2 could be the start of an extended container therefore linux names the first extended partition sda5 to not conflict with the 4 primary partition device names.