benkyoumashou.com/blog/japanese-numbers/
Guide to Japanese numbers from 1 to 100 and beyond, covering the two counting systems, irregular readings for 4, 7 and 9, sound changes in hundreds and thousands, and the base-10,000 grouping system.
VocabularyGrammarCountersKatakanaJLPT N5BeginnerHiraganaJLPT