It is a verbal is a math puzzle in which digits are changed with alphabets and symbols.the various types of cryptarithm are:::
1. Alphametic:::: a long addition sum  in which a set of word is written.
2. Skeletal division :::a long division in which all digits are replaced by symbols.
3. Digimetic::::digimetic is a type in which digits are used to represent other digits. 
hope it is enough