Counting number of posts in multiple (sub)categories using shortcode

I'm making a new cycling team website and on the home page i have 3 different type of stats: Win, Podium and top-10

Now i want the number of the stat go up if i post something with for instance the category: Podium But i want it to go 2 up if i select the categories: 1-podium / 2-podium ETC

So in short, i want the count number go up if i post something while selecting one or more categories. If i select one category, the number needs to go up by 1, if i add 2 it needs to go up by 2 etc.

I'm relative new to Wordpress so i don't know where to make the code and how to make the shortcode to the code.

Can someone please help me?