---
title: "为什么在 Windows 计算器中输入 200 + 10% 会得到 220？"
url: "https://reamcp.dev/zh-cn/cases/why-does-200-10-give-220-in-windows-calculator-d80c96"
source: "https://rea.run/showcase/windows-calculator-percent"
source_type: "website"
author: "REA community"
author_handle: "REA community"
stars: 0
category: "CTF 与学习"
categories: ["ctf-learning"]
tags: []
added: "2026-10-13T03:57:33.902Z"
updated: "2026-10-13T03:57:33.902Z"
locale: "zh-cn"
content_locale: "zh-cn"
---

# 为什么在 Windows 计算器中输入 200 + 10% 会得到 220？

解释熟悉的百分号键怪癖，并结合公开、开源的计算器代码来验证该解释。

## Description

列入原因：已对照开源代码进行核实；具有教育意义。

## Original README

Why 200 + 10% can yield 220 — and how to check explanations against Microsoft’s public sources.