How can customer select qty of variants on product page?

Site URL: https://www.head-to-socks.com

We sell 15 varieties of yoga socks as single packs, double, etc... up to 6 pack mix and match. When the customer selects a multi-pack, say a 6 pack for example, I add 6 "select" forms on the product page. When the user clicks the drop down, the 15 varieties come up as options. They do this 6 times and that data is sent to me when they checkout. The price doesn't change because they are paying for a 6 pack regardless of the variation they select on the product order page.

I want to add a 50 and 100 pack options, but listing 50 drop downs is not a good way. Is there a way on the product order page to list my 15 variations and next two each variation have a dropdown selection 0 to 50 for the quantity of pairs of socks they want for that variety AND have a running total of socks so they can't select more (or less) than 50 socks?