A 4 digit number 8a43 is added to another 4 digit number…

A 4 digit number 8a43 is added to another 4 digit number 3121 to give a 5 digit number 11b64, which is divisible by 11, then (a+b)=?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #68767