くく
multiplication table; times table
Common word Also written 九々
Noun
トムは、難むずかしい問題もんだいはスラスラ解とけるのに、九九くくとか簡単かんたんな計算けいさんが苦手にがてなんだよ。
Tom can solve difficult problems with ease, but he is weak when it comes to simple arithmetic such as the times table.