自由转换
如何将百分数转换为小数?
- 除以100(将数字向右移动两位)
- 6%的小数是6 ÷ 100 = 0.06
- 40%的小数是40 ÷ 100 = 0.4
- 350%的小数形式是350 ÷ 100 = 3.5
- 小数形式为0.2 ÷ 100 = 0.002
如何将小数转换成百分数?
- 乘以100(将数字向左移动两位,并加一个%号)
- 0.35的百分比是0.35 × 100 = 35%
- 1.32的百分比为1.32 × 100 = 132%
- 0.004作为百分比是0.004 × 100 = 0.4%
如何将小数转换成分数?
- 如果它有一位小数点后,写10以上的数字
- 0.3是
" class="Wirisformula" role="math" alt="3 / 10" style="vertical-align:-17px;height:47px;width:27px">3 10 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} - 1.1是
" class="Wirisformula" role="math" alt="11 / 10" style="vertical-align:-17px;height:47px;width:27px">11 10 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} - 如果它有两位小数点后,写出超过100的数字
- 0.07是
" class="Wirisformula" role="math" alt="7 / 100" style="vertical-align:-17px;height:47px;width:36px">7 100 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} - 0.13是
" class="Wirisformula" role="math" alt="13 / 100" style="vertical-align:-17px;height:47px;width:36px">13 100 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} - 30.01是
" class="Wirisformula" role="math" alt="3001 / 100" style="vertical-align:-17px;height:47px;width:45px">3001 100 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} - 如果有n小数点后,写10以上的数字n
- 0.513是
" class="Wirisformula" role="math" alt="513 / 1000" style="vertical-align:-17px;height:47px;width:45px">513 1000 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} - 0.0007是
" class="Wirisformula" role="math" alt="分子7除以分母10格000的分数" style="vertical-align:-17px;height:47px;width:58px">7 10 000 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} - 学习简单的循环小数作为分数
- 0.33333……=
" class="Wirisformula" role="math" alt="0.3与点顶部" style="vertical-align:-6px;height:26px;width:24px">是0 . 3 ˙ {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} " class="Wirisformula" role="math" alt="1/3" style="vertical-align:-17px;height:47px;width:18px">和0.66666…=1 3 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} " class="Wirisformula" role="math" alt="0.6,上面有圆点" style="vertical-align:-6px;height:26px;width:24px">是0 . 6 ˙ {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} " class="Wirisformula" role="math" alt="2 / 3" style="vertical-align:-17px;height:47px;width:18px">2 3 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} - 整数可以写成分数形式(把它们写成除以1)
- 5是
" class="Wirisformula" role="math" alt="5 / 1" style="vertical-align:-17px;height:47px;width:18px">5 1 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true}
如何将百分数转换成分数?
- 写出百分数除以100
- 37%是
" class="Wirisformula" role="math" alt="37 / 100" style="vertical-align:-17px;height:47px;width:36px">37 100 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true}
如何将分数转化为小数?
- 分数除以10的幂更快
" class="Wirisformula" role="math" alt="3 / 5 = 6 / 10" style="vertical-align:-17px;height:47px;width:61px">也就是0.63 5 = 6 10 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} " class="Wirisformula" role="math" alt="7除以20等于35除以100" style="vertical-align:-17px;height:47px;width:79px">也就是0.357 20 = 35 100 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} " class="Wirisformula" role="math" alt="1 / 500 = 2 / 1000" style="vertical-align:-17px;height:47px;width:97px">也就是0.0021 500 = 2 1000 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true}
如何将分数转换成百分数?
- 把分数变成小数(见上文),然后乘以100
" class="Wirisformula" role="math" alt="4 / 5 = 8 / 10" style="vertical-align:-17px;height:47px;width:61px">也就是把0.8写成小数,0.8 × 100 = 80%4 5 = 8 10 {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true}
考试技巧
- 计算器可以用来检查分数和小数之间的转换(即使题目说不用计算器也可以)
循环小数
什么是循环小数?
- 一个理性的数字是任何可以写成整数(整数)除以另一个整数的数字
- 数字:写为
" class="Wirisformula" role="math" alt="P / q" style="vertical-align:-17px;height:47px;width:19px" loading="lazy">最简形式,其中p而且问都是整数是有理数p q {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true}
- 数字:写为
- 当你写有理数作为小数,你要么得到一个小数,停止(例如¼= 0.25),称为“终止十进制,或以某种模式重复的十进制(例如,1 / 3 = 0.333333…),称为反复出现的“小数
- 循环部分可以用一个点(或在第一个和最后一个循环数字上的点)来写。
" class="Wirisformula" role="math" alt="0.3333……空格等于空格0.3,上面有点" style="vertical-align:-6px;height:26px;width:114px" loading="lazy">0 . 3333 . . . = 0 . 3 ˙ {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} " class="Wirisformula" role="math" alt="0.121212……空格等于0.1点在上面2点在上面" style="vertical-align:-6px;height:26px;width:137px" loading="lazy">0 . 121212 . . . = 0 . 1 ˙ 2 ˙ {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true} " class="Wirisformula" role="math" alt="0.325632563256……等于0.3,上面有点25,上面有点6" style="vertical-align:-6px;height:26px;width:205px" loading="lazy">0 . 325632563256 . . . = 0 . 3 ˙ 25 6 ˙ {"language":"en","fontFamily":"Times New Roman","fontSize":"18","autoformat":true}
怎么把循环小数写成分数?
写出小数点后的前几位来表示循环模式,然后:
- 写出循环小数F =…(使用一些类似的方法x=…)
- 两边同时乘以10反复直到两行有相同的循环小数部分(按顺序)
- 减去这两条线
- 两边同除得到f=…(如果有必要,可以取消以获得最低分数)
工作的例子
写
使用一个变量来表示这个数字。
两边同时乘以100,得到另一个小数部分重复出现的数字。
这两个方程相减以消去小数部分。
两边同时除以99
在计算器中输入分数,并更改为小数以检查是否正确。