careless mistake

Translations
небрежная ошибка
She made a careless mistake on the test.
Она сделала небрежную ошибку в тесте.
Definitions
A careless mistake is an error made due to a lack of attention, thought, or consideration, often resulting from oversight or negligence rather than a lack of knowledge or skill.
Words
mistake

noun
ошибка
careless

adjective
небрежный