There's interest here in arithmetic operations on NaN . I've just seen a product listed as costing NaN pounds to buy a null amount. That was written as £NaN/null.
The bargain item is Glade Shake & Vacuum Citrus, and you can see it at https://www.tesco.com/groceries/en-GB/products/253732570
Searching on this site for 'NaN' brings up many entries for https://en.wikipedia.org/wiki/Naan bread.
with best regards