Questions & Answers about Odečet je správný.
Because správný has to agree with odečet.
- odečet is a masculine singular noun
- so the adjective also appears in the masculine singular nominative form: správný
A few comparison examples:
- výpověď je správná = the statement is correct
- číslo je správné = the number is correct
- odečet je správný = the reading/subtraction is correct
So the ending -ý is there because of grammatical agreement.
It is in the nominative case, because it is the subject of the sentence.
In Odečet je správný:
Since správný describes the subject, it is also in the nominative.