Breakdown of Он придумал новую игру.
он
he / it (for a masculine noun) / it (for a neuter noun)
новый
new
игра
game
придумать
to think up, to invent (perfective)
Questions & Answers about Он придумал новую игру.
Why do новая игра change to новую игру here?
They are the direct object of the sentence, which means they are the thing being invented. This requires the accusative case. For feminine nouns ending in -а, the dictionary ending changes to -у (игру), and matching adjectives ending in -ая change to -ую (новую).
I know думал means thought. How does adding при- change the meaning to invented?
The prefix при- often adds the idea of bringing an action to a successful result or arrival. While думать is the ongoing process of thinking, придумать means you thought until you produced a result, meaning you came up with or invented something.
Why did we use the perfective verb придумал instead of an imperfective verb?
We use the perfective aspect here because the action is completely finished and has a clear result. He successfully created a specific new game, rather than being in the ongoing, unfinished process of inventing it.