First grade teachers hooked students into learning about the “FLOSS” rule during phonics by pretending to be dentists. The floss rule is a phonics spelling rule that states that when a one-syllable word ends with a short vowel and the letter f, l, s, or z, the final letter should be doubled. The rule is named after the word "floss", which contains the letters f, l, and s and follows the rule. What a fun way to learn how to spell!