《计算机专业英语》电子教案_第3章.pptVIP

Computer English ;Key points:  useful terms and definitions of Number system and Boolean AlgbraDifficult points:  Conversion of the Number Systems and Boolean Algbra;Requirements:;New Words Expressions: hexadecimal adj.十六进制的; n.十六进制 radix n.根, 基数 octal adj.八进制的; n.八进制 alphabet n.字母表 fractional adj.分数的, 小数的 whole number n.整数 remainder n.余数 significant figure n.有效数字 quotient n.商 algorithm n.算法 complement n. 补码，余角 carry n.进位 ;The use of the microprocessor requires a working knowledge of binary, decimal, and hexadecimal numbering systems. This section provides a background for those who are unfamiliar with number systems. Conversions between decimal and binary, decimal and hexadecimal, and binary and hexadecimal are described.;Before numbers are converted from one number base to another, the digits of a number system must be understood. Early in our education, we learned that a decimal, or base 10, number was constructed with 10 digits: 0 through 9. The first digit in any numbering system is always a zero. For example, a base 8 (octal) number contains 8 digits: 0 through 7; a base 2 (binary) number contains 2 digits: 0 and 1. ;If the base of a number exceeds 10, the additional digits use the letters of the alphabet, beginning with an A, For example, a base 12 number contains 12 digits: 0 through 9, followed by A for 10 and B for 11, Note that a base 10 number does not contain a 10 digit, just as a base 8 number does net contain an 8 digit. The most common numbering systems used with computers are decimal, binary, and hexadecimal (base 16). (Many years ago octal numbers were popular.) Each system is described and used in this section of the chapter.;Once the digits of a number system are understood, larger numbers are constructed by using positional notation. In grade school, we learned that the position to the left of the units position was the tens position, the position to the left of the tens position was the hundreds posit