What an arithmetic captcha is
2026-03-09 · Arithmetic captchas
The image shows a sum, such as 14 + 9, and the value to type is the result, 23.
An arithmetic captcha prints an expression and wants the result. 14 + 9 should be submitted as 23, not as 14+9.
Send math: true and do not send hindi unless the words are Devanagari number words. The engine is math. text is 23. expression is 14+9. raw is what was read off the image.
On 120 live arithmetic captchas the engine scored 95%, and 98.3% of the reliable answers were correct. Unreliable ones are free. Refresh those.
The math model is faster than the text model, about 6 ms on the measured setup, because the grammar of a sum is narrow.
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