微控制器具有较强的加、减、乘、除等数学运算功能，这些运算可直接对8位无符号二进制数进行运算。利用溢出标志，还可以把加、减法运算用于有符号数的运算；用十进制调整指令，又可使加法运算直接用十进制（BCD码）来进行。-Micro-controller has strong add, subtract, multiply, divide and other math functions, these operations can be directly on the 8-bit unsigned binary number for calculation. Using overflow flag, but also can add, subtract the number of operations for signed　decimal adjust instruction, but also make direct use of the decimal addition operation (BCD code) to carry out.