読 read

I can't seem to get the hang of suDOKU, Perhaps I'll read a book about it.

If you say the book sold a lot of copies, I'll read it.

yep yep. ★★★☆☆
訓 (kunyomi) + 読 (read) = 訓読み (yep yep.)

The kanji pronunciation one uses in compound words. ★★★☆☆
音 (sound) + 読 (read) = 音読み (The kanji pronunciation one uses in compound words.)

yep.

to subscribe ★☆☆☆☆
購 (subscribe) + 読 (read) = 購読 (to subscribe)