How computerisation can lead to unemployment?

Any taks that were originaly undertaken by humans and then become automated means that the human labour is no longer required for the role.

Examples of this are; Accounting. Originall all details of a company were written in to books (ledgers), The information was then filed. It required many individuals in large companies to write in the data accurately, then find entries and write in paymenst against the account and new balances. This is now dont i seconds by one person rather than many.

Banks have exactly the same system originally all ledgers filled with customer account information, monies in and out now its dont by one person at a computer or by OCR systems when documents hare been read in at speed.

Mail systems (postal) were all sorted by hand - now massive sorting offices can sort millions of letters and parcels in hours rather than over night thus speeding up the system and reducing the labour demands