➕ 竖式加法计算器（列竖式）Long Addition Calculator
用竖式（列竖式）把两个或多个非负整数或小数相加，按小数点对齐，逐列显示进位和每一步，支持任意长度的大数，适合检查作业。Add two or more non-negative whole numbers or decimals by long addition, lined up on the decimal point, with the carry and working shown for each column and no limit on length — handy for checking homework.
使用说明与常见问题How-to & FAQ
「竖式加法计算器（列竖式）」是什么？What is the Long Addition Calculator tool?
用竖式（列竖式）把两个或多个非负整数或小数相加，按小数点对齐，逐列显示进位和每一步，支持任意长度的大数，适合检查作业。Add two or more non-negative whole numbers or decimals by long addition, lined up on the decimal point, with the carry and working shown for each column and no limit on length — handy for checking homework.
如何使用「竖式加法计算器（列竖式）」？How do I use the Long Addition Calculator tool?
在「竖式加法计算器（列竖式）」中，填写上方字段等参数，结果会随输入实时计算并显示在下方。In the Long Addition Calculator: Fill in the fields above; results are recalculated instantly as you type.
竖式加法怎么做？How does long addition work?
把各数按个位（有小数时按小数点）对齐，从最右边一列开始相加；一列的和满 10 就写下个位数，把十位数作为进位加到左边一列。Line the numbers up on the ones place (or the decimal point) and add from the rightmost column; when a column reaches 10 or more, write its last digit and carry the rest to the next column left.
小数怎么对齐？How are decimals lined up?
按小数点对齐，位数少的在右边补 0，例如 12.5 + 0.75 看作 12.50 + 0.75。结果去掉末尾多余的 0。On the decimal point, padding shorter ones with zeros on the right: 12.5 + 0.75 becomes 12.50 + 0.75. Trailing zeros are dropped from the answer.
计算精度如何？How precise are the results?
「竖式加法计算器（列竖式）」使用 JavaScript 双精度浮点数（约 15–16 位有效数字）；极大或极小的数值可能存在精度误差。The Long Addition Calculator uses double-precision floating point (about 15–16 significant digits); very large or very small values may lose precision.
「竖式加法计算器（列竖式）」免费吗？需要注册吗？Is the Long Addition Calculator free? Do I need an account?
「竖式加法计算器（列竖式）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Long Addition Calculator is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.