The document discusses converting decimal numbers to binary numbers. It explains that the integer and fractional parts of a decimal number are dealt with separately. To convert the integer part, the number is repeatedly divided by 2 and the remainders are written down and taken in reverse order to form the binary number. To convert the fractional part, the number is repeatedly multiplied by 2 and the integer parts are taken in forward order. Examples are provided of converting the decimal numbers 125, 0.4375, and 17.35 to their equivalent binary numbers.