Section outline

  • Bullseye
    ::红心

    Just as  you use the well-known symbol = to represent equality,  you can also use symbols to represent inequality . These symbols are called relational operators when used in computer programming.
    ::正如您使用众所周知的符号 = 来代表平等, 您也可以使用符号来代表不平等。 这些符号在计算机编程中使用时被称为“ 关系操作员 ” 。

    Jack is a game developer and is writing the code for a video game.  In the interactive below, you will play the game to gain as many points as possible, moving to the next level when you get a certain number of points. Think about how you would represent this situation with an inequality statement.
    ::Jack 是一个游戏开发者, 正在撰写游戏游戏代码 。 在下面的互动中, 您将玩游戏以获得尽可能多的点, 当您得到一定数量的点时会移动到下一个级别 。 想想您如何用不平等声明来表达这种情况 。

    INTERACTIVE
    Watermelon Launch
    minimize icon
    • Drag the red point to set the angle and how far to launch the watermelon.
      ::拖曳红色点以设定角和发射西瓜的距离。
    • Click the buttons to launch the watermelon, try another launch, and start a new game.
      ::单击按钮以启动西瓜,尝试另一次发射,并启动新游戏。
    • You get 3 launches every game and your points get added up in the end. If you score at least 35 points, you can move to the next level.
      ::每场比赛有3次发射,最后你的分数加起来。如果得分至少35分,你可以升到下一个水平。
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    Jack wants to write a function so that if the player scores at least 35 total at the end of their three attempts, they will advance to the next level. 
    ::杰克想要写一个函数, 这样如果玩家在三次尝试结束时 总共得分至少35分, 他们就会升到下一个级别 。

     

    Progress
    0 / 4
    1.

    If Jack wants the player to score a total of at least 35 points at the end of three attempts to move on to the next round, which of the following total scores would allow a player to advance to the next level and why?
    ::如果杰克想让玩家在三次尝试结束后 得分至少35分 来进入下一轮比赛, 那么接下来的总得分中, 哪一个能让玩家升到下一个级别, 为什么?

    Select all that apply
    a

    30, because @$\begin{align*}30\lt 35.\end{align*}@$
    ::30, 因为 @$\ begin{ align} 30\lt 35.\ end{ align} $

    b

    15, because @$\begin{align*}15\lt 35.\end{align*}@$
    ::15, 因为 @$\ begin{ align} 15\ lt 35.\ end{ align} $

    c

    45, because @$\begin{align*}45\gt 35.\end{align*}@$
    ::45, 因为 @$\ begin{ align} 45\ gt 35.\ end{ align} $

    d

    35, because @$\begin{align*}35=35.\end{align*}@$
    ::35 因为 @$\ begin{ align} 35=35。\ end{ align} $

     

     

    Inequality Symbols
    ::不平等符号

    You are already familiar with greater than and less than symbols, > and <. However, there are two symbols that you may not have not seen before .
    ::您已经熟悉了大于或小于符号、 > 和 < 。 但是,有两种符号你以前可能没见过。

    ≥   The 'greater than or equal' symbol means that an unknown value could be either more than or  the same as  another number. This symbol  can also be used for ' at least ' a value.
    ::`大于或等于'符号表示未知值可能大于或等于其他数字。此符号也可以用于“至少”一个数值。

    ≤   The 'less than or equal' symbol means that an unknown value could be either  less than or  the same as  another number.  This symbol can also be used for ' at most ' a value.
    ::`小于或等于'符号表示未知值可能小于或等于其他数字。该符号也可以用于“最多”的值。

    Discussion Questions
    ::讨论问题 讨论问题

    1. What values could A represent in the inequality A ≥ 10 ?
      ::A在不平等中可以代表什么价值?
    2. Could 10.5 be the value of A ?
      ::会不会是A值10.5?
    3. What values could B represent in the inequality B ≤ 10 ?
      ::B在不平等 B 10中可以代表什么价值?
    4. Could 10.5 be the value of B ?
      ::B值是10.5吗?
    5. Could 9 ⅔ be the value of B ?
      ::会不会是B值9 2⁄3?

    Use the interactive below to practice matching inequality statements with inequality symbol notations.
    ::使用以下互动方式,将不平等声明与不平等符号符号相匹配。

     

    INTERACTIVE
    Matching Inequality Symbols
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    • Try to match the inequality symbol with its phrasing by clicking the correct tile.
      ::试着单击正确的牌, 将不平等符号与其语法匹配 。
    • Match as many tiles as possible within 15 seconds.

      ::15秒内尽可能匹配更多的瓷砖 。
    • The game will begin once you press Start.
      ::一旦您按下启动键, 游戏就会开始 。
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    Matching Inequalities
    ::匹配不平等

    Example
    ::示例示例示例示例

    Recall from the beginning of the this lesson that  Jack is a game developer writing  a function so that if the player scores at least 35 points after three launches ,  they will  advance to the next level. If the player's total score is represented by  s ,  how could  you write this as an inequality?
    ::从这个教训的开头, 杰克是一个游戏开发者, 正在写一个函数, 这样如果玩家在三次发射后至少得35分, 他们就会升到下一个级别 。 如果玩家的总得分由 s 表示, 您如何将此写成不平等 ?

    s ≥ 35 .

    ::第35条。

    Through this interactive, practice transforming real-world situations into inequality statements by choosing the appropriate inequality symbol.
    ::通过这一互动性做法,通过选择适当的不平等符号,将现实世界状况转化为不平等声明。

     

    INTERACTIVE
    Matching Inequalities
    minimize icon
    • Choose the correct inequality from the drop down menu.
      ::从下调菜单中选择正确的不平等。
    • Check your answer with the "Check" button.
      ::用“ 检查” 按钮检查您的回答 。
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    Inequalities with a Variable
    ::与变量的不平等

    An inequality states that one value is less than, greater than, 'less than or equal to' or 'greater than or equal to' another value using the symbols <, >, ≤, and ≥. Thus far, you have worked with inequalities where the variable appears to the left of the inequality symbol.
    ::不平等表示一个值小于、大于或大于“ 小于或等于”或“大于或等于”另一个值,使用符号 < 、 > 、 和 。 到目前为止,您一直致力于不平等,变量出现在不平等符号的左边。

    Inequalities can also be expressed with the number to the left of the symbol. For example, the statement “8 is greater than a number" would be written as 8 > x. However, it is generally easier to read an inequality with the variable on the left.
    ::符号左侧的数字也可以表示不平等。例如,“8大于数字”的语句将写为8> x。然而,通常更容易读懂左边变量的不平等。

    To reverse an inequality, switch the values and flip the sign. The statement “8 is greater than a number” can be thought of as "a number is less than 8." Show this relationship by reversing the inequality: x < 8.
    ::为了扭转不平等, 转换数值并翻转符号 。 “ 8 ” 的语句“ 8 大于一个数字 ” 可以被理解为“ 数字小于 8 ” 。 通过扭转不平等来显示这种关系 : x < 8 。

    Use the interactive below to practice identifying whether a value is included in an inequality.
    ::利用以下互动手段,确定是否将某一价值纳入不平等。

     

    INTERACTIVE
    Inequalities with a Variable
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    • Click the "Yes" or "No" buttons to answer the question about the inequality.
      ::单击“是”或“否”按钮回答关于不平等的问题。
    • Click the "Try New Question" button to try different questions.
      ::单击“ 尝试新问题” 按钮来尝试不同的问题 。
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     Summary
    ::摘要

    • When writing inequality statements, make sure to use the correct symbol:
      ::在撰写不平等声明时,确保使用正确的符号:

    includes  x : excludes  x : below  x : ≤ < (less than or equal to) (less than) above  x : ≥ > (greater than or equal to) (greater than)

    ::包括 x: excludes x: below x: {( 小于或等于) x: {( 大于或等于) x: {( 大于)

    • To reverse an inequality, switch the values and flip the signs. For example,  5 ≤ x   is the same as  x ≥ 5.  
      ::为了扭转不平等, 转换数值并翻转符号。 例如, 5x 和 xx5 相同 。