Can I translate it as "um é menor do que dois"?
Yup! In math this sign is "maior que" and "menor que". The literal translation is "greater than" and "less than". "Menor que" is better than "menor do que"
i think maybe here Duolingo means to ask the translation of "less than", which has to be "menos que". For "menor que", I guess they will require it to be "smaller than". Right?
Uhu.... but i think both should be accepted, the literal way (less than = menos que) and the 'mathematical' way hehe. 1 < 2 one is less than two / um é menor que dois
Why is menor que still being marked incorrect? 7 years!