I just learned 算定する, to calculate. The reading is さんていする , taking both their respective on’yomi readings from the kanji. Now, the reading explanation says: ‘This is a jukugo word, which usually means on’yomi readings from the kanji. If you know the readings of your kanji you’ll know how to read this as well.’ However, I don’t understand why this is jukugo. I looked jukugo up on tofogu where it says ‘A two-kanji (or more) compound usually takes the on’yomi readings. These are called jukugo 熟語. There are no hanging-on hiragana (okurigana) sticking out from the word. (my emphasis)’ So, am I missing something? Or is this a mistake?