Not the best CAPTCHA...
A math problem is the worst CAPTCHA ever.
A CAPTCHA (which stands for "Completely Automated Public Turing Test To Tell Computers and Humans Apart") is meant to be a lightweight challenge-response test to distinguish inputs from humans versus machines. The point of a CAPTCHA is to provide some image and then ask the user to perform some action involving invariant recognition, segmentation, or contextual awareness which is easy for a human to do, but very hard for a computer to do.
Unfortunately, computers are exceptionally good at performing lots of computations very quickly so \( 6+1 \) is perhaps the worst CAPTCHA you can come up with.
