Why is more space taken than files actually weigh?

Question

Windows

Copied the files to a flash drive. Out of 10 gigs shows 45? Why is that?

Answer 1

The files are small, the cluster size is large.
The file is smaller than a cluster, and in any case it occupies at least one cluster.
Apparently there is a cluster of 64 kilobytes. And the average file size is around 30 kilobytes.
In general, the situation is normal.
On a flash drive, making a large cluster size is a good practice.