Bigdecimal

//加法
        BigDecimal result1 = num1.add(num2);
        BigDecimal result12 = num12.add(num22);
 
        //减法
        BigDecimal result2 = num1.subtract(num2);
        BigDecimal result22 = num12.subtract(num22);
 
        //乘法
        BigDecimal result3 = num1.multiply(num2);
        BigDecimal result32 = num12.multiply(num22);
 
        //绝对值
        BigDecimal result4 = num3.abs();
        BigDecimal result42 = num32.abs();
 
        //除法
        BigDecimal result5 = num2.divide(num1,20,BigDecimal.ROUND_HALF_UP);
        BigDecimal result52 = num22.divide(num12,20,BigDecimal.ROUND_HALF_UP);