易しい

On

易:エキ

Kun

易:やさ(しい)

この問題は易しいです。

This problem is easy.

Remember: i-adjectives conjugate directly, while na-adjectives need な before nouns and だ/です at the end. Try to learn this with its opposite adjective for stronger memorization. A fundamental N5 word — you'll use this in almost every conversation.