Your figures are correct but beware that with the 4MHz clock the error is about 8% which will almost certainly cause problems. As a rule of thumb, the safe error limit is about 2%
The '0x' in front of the number just means the following characters are in hexadecimal (base 16) radix. 0x0A is equivalent to 10 in decimal. It is quite normal for programmers to write in hexadecimal 'hex' because it's easier to visualize the bit pattern of a hex number than it's equivalent decimal version. Think of hex as a shorthand way of writing in binary, each of the characters decodes to 1 of 16 easy to remember bit patterns.
Brian.