The MySQL BigInt isn't that big. 64 bits. If you want to store larger numbers, store them as text. But what if you want to add numbers stored in text? This procedure adds two text numbers of any size and returns the result as text.

unknown 7ccc4b5b47 Initial upload. 8 months ago
BigAdd.txt 7ccc4b5b47 Initial upload. 8 months ago
README.md 7ccc4b5b47 Initial upload. 8 months ago

README.md

MySQL---BigAdd

Add two base 10 numbers and return a number in base 10 (varchar)