• Basic forms
• 当てる — to apply / to hit / to guess / base form
• 当てます — politely apply / hit / masu form
• 当てた — applied / hit / guessed / ta form
• 当てて — apply and … / hit and … / te-form
• 当てない — do not apply / negative
• 当てれば — if (you) apply / conditional
• Other common forms
• 名前を当ててください — please guess the name
• 日光に当てる — to expose to sunlight
• ヒントを当てられる — can guess the hint / potential
• More
• 当てよう — let’s apply / let’s guess / 〜よう form
• 当てなかった — did not apply / past negative

当てる（あてる）は一段動詞（ichidan）。Stem is 当て. Forms follow the regular pattern: 当てる → 当てて → 当てた → 当てます. Common uses include “to hit,” “to guess,” and “to apply/expose” something to something.

• Basic forms
• 当たる — to hit / to be correct / to strike / base form
• 当たります — hits / is correct / masu form
• 当たった — hit / was correct / ta form
• 当たって — hitting / being correct and … / te-form
• 当たらない — does not hit / is not correct / negative
• 当たれば — if it hits / if correct / conditional
• Other common forms
• 宝くじに当たる — to win the lottery
• 日が当たる — sunlight hits
• 予想が当たる — the prediction is correct
• More
• 当たらなかった — did not hit / was not correct
• よく当たる — very accurate (e.g., fortune-teller)

当たる（あたる）is a godan (う-verb). It covers meanings like “to hit,” “to be correct,” “to strike,” and “to win.” The contrast with 当てる is important: 当てる is something you do, 当たる happens on its own.