what are these numbers?

these are possibly ‘page of pages’ numbers; i.e. the number of the paginated page you are on and the total number of paginated pages –

example:
your site has 63 posts; there are 10 posts per page; you are on the front page – then it would show 1/7

to remove them, try to find the code for the <title> tag, probably in header.php

as you tagged this topic with a seo plugin, check if this has options to show/hide these numbers.

I am not really sure what i am looking for. Please take a look.

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i was referring to this line: <title><?php wp_title(''); ?></title> however, this is clearly overwritten by your seo plugin;

double check, if there is anything in the plugin settings or options that refers to ‘pagination’ or ‘paged’ or similar.