return c >= 0x0030 && c <= 0x0039 
        || c >= 0x0660 && c <= 0x0669 
        || c >= 0x06F0 && c <= 0x06F9 
        || c >= 0x0966 && c <= 0x096F 
        || c >= 0x09E6 && c <= 0x09EF