If 'm' is your message of 16 bits, and you are calculating a CRC of 8 bits (CRC-8), then let 'x' be message 'm' appended by 7 zeroes. Let 'y' be a "" number. Divide 'x' by 'y', until you obtain a remainder that is not divisible further. Take this remainder and subtract it from the "magic" number 'y' and add this result to 'x' to obtain 'z'. 'z' is now a multiple of the "magic" number 'y' and dividing 'z' by 'y' will give a zero remainder. 'z' can now be transmitted to the receiver. The receiver will perform this division and check if the remainder is zero to confirm that there were no errors in transmission. The message can be recovered by simply reading the most significant 16 bits in the 24 bit transmission. 