The letter C can represent the sound "k" as in "cut" or the sound "s" as in "cent".
Teaching learners how this works and why it's a good thing when we start adding suffixes to words can be tricky, especially if they don't really understand "if-then" sentences yet.
Note that the spelling CC is sometimes followed by a letter E but the sound is still "k", e.g. soccer, sicced (as in "I sicced the dog onto the burglar and she ran off"). CC is like other doubled letters, its main purpose is to tell you to say a "short" vowel before it, as in raccoon, Mecca, piccolo, broccoli and buccaneer. Typically, but not always, we write CK instead of CC.
The spelling C+C might also represent a "k" sound at the end of one syllable followed by a "s" at the start of the next syllable, as in "accede", "accent", "accept", "access" and "coccyx".
Also, either a single or double C might represent a "ch" sound in some Italian-origin words e.g. cello, Botticelli, bocce (click here for more).