Math captcha is too simple

[Дмитрий Пантелеев]

Hello

Even on the 5th level usually you just need to calculate the last digit, not the whole answers, because the last digits of the answers are usually different.

I'm offering that there should be the right answer x(2 or 3 digits), and all others 4 must be in the range from x - 20 to x + 20, and 3 of them should have the same last digit, while the other two should have another one, but they also share this digit. Also this another last digit must be odd, if correct one is odd, and even, if the correct one is even

FOr example, 24*13= 312, 316, 306, 322, 336.

[Александр Гончаренко]

Calculus captcha? Some simple integrals to begin the day with... Just kidding.

[Дмитрий Пантелеев]

But this is really a problem for me ;-) My mind is not awake after calculating 5 1-digit equations, and I easily can sleep immediately after that.

So, the only option for me is qr - captcha, while I like the math one.

[Александр Гончаренко]

I doubt that more complicated primers will do the trick either — you can just solve them and continue to sleep happily. In my experience, sometimes even killing three consecutive alarms on different devices sometimes doesn't help to wake up if I'm intended "to get some more" :D But I have some rumour that calculus captcha is probably to be...

[blablubbb]

How about square-root captchas?

e.g.: Calculate the square-root of 3 with 2 (or 3) digits accuracy. (1.7). That can be done in the head, but it is really not too easy as long as the squareroot is not an integer.

[Дмитрий Пантелеев]

Another variant could be keyboard to enter answers, not just choices