章节大纲

  • Cranes
    ::起重车

    lesson content
    Crane Lifting a Large Object

    Inequalities are used to compare quantities in situations where the quantities may not be equal , meaning that  one value is greater or less than another. For example,  you can state that -5 is greater than -8.  You can also use inequalities to state information about an unknown quantity.
    ::在数量可能不相等的情况下,用不平等来比较数量,这意味着一个值大于或小于另一个值。例如,您可以声明 -5 大于 -8。您也可以使用不平等来说明未知数量的信息。

    Discussion  Question
    ::讨论问题

    A crane can carry a maximum of 18 tons. If a crane is lifting a beam to put on a building, what do we know about the weight of the beam?
    ::起重机最多可携带18吨。如果起重机举起横梁在建筑物上铺设,那么我们对波束的重量了解多少?

     

    Comparing with an Unknown
    ::与未知

    Inequalities are a mathematical concept  that rely on   verbal rules . Before  you learn about the mathematical symbols and statements  you can use to represent an inequality , you should first  understand the general language used to describe an inequality.
    ::不平等是一种依赖语言规则的数学概念。在学习数学符号和表达不平等的语句之前,您应该首先理解用来描述不平等的一般语言。

    Use the interactive to identify possible values for the unknown that make the given statement true.
    ::使用互动来识别使给定语句变为真实的未知语句的可能值 。

     

    INTERACTIVE
    Compare with an Unknown
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    • Enter a number that satisfies the inequality statement given.
      ::输入符合所给出不平等声明的编号。
    • Click the button when it appears to try entering new values or answering a new question.
      ::当似乎尝试输入新值或回答新问题时单击按钮。
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    Guess the Number
    ::猜测数字

    Computers  often need to find a specific item in a randomly arranged set of numbers.
    ::计算机往往需要在随机排列的一组数字中找到具体的项目。

    Here is a simple example of this:  Find the position of the 6 in the following set of numbers.
    ::以下是一个简单的例子:在以下一组数字中查找 6 的位置。

    { 3 , 4 , 1 , 7 , 5 , 10 , 8 , 9 , 1 , 6 , 4 , 2 }

    Discussion Questions
    ::讨论问题 讨论问题

    1. What strategy did you use to find the six?
      ::你用什么策略来找到那六个人?
    2. What if the list had 1,000 or 1,000,000 numbers in it? Would you be able to use the same strategy?
      ::如果名单上有1 000或1 000万个数字呢?你能采用同样的策略吗?

    Computers use algorithms to identify the position of the number as quickly as possible. One possible algorithm involves repeatedly checking whether a number is greater than or less than a randomly chosen number.
    ::计算机使用算法来尽快识别数字的位置。 一种可能的算法是反复检查数字是否大于或小于随机选择的数字。

    In the interactive below, you will write inequality statements to determine what number the interactive is thinking of between 1 and 100.
    ::在下文互动部分,您将撰写不平等声明,以确定互动的1至100之间的人数。

     

    INTERACTIVE
    Mystery Number Guessing Game
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    • Use your knowledge of inequalities to try and guess the correct number between 1 and 100!
      ::使用您对不平等的知识来猜一到一百之间的正确数字!
    • You can narrow down your options by using the "Less Than" and "Greater Than" options, and finally try guessing the exact number itself.
      ::您可以通过使用“ Less Than” 和“ greater than” 选项缩小选项范围, 最终尝试猜测准确数字本身 。
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    Discussion Question  
    ::讨论问题

    Which strategies were more effective in helping to identify the mystery number in the fewest guesses? Write out a series of steps that you believe should be followed to find the answer as quickly as possible.
    ::哪些策略能更有效地帮助识别最小猜想中的神秘数字? 写出一系列你认为应该遵循的步骤,以便尽快找到答案。

     

    Matching Statements
    ::配对语句

    For the following interactive, practice writing inequality statements from real world situations.
    ::对于以下互动活动,实践从现实世界状况中撰写不平等声明。

     

    INTERACTIVE
    Matching Statements
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    • Choose from the drop down to make the statement correct.
      ::从下拉中选择, 使语句正确 。
    • Check your answers with the "Check" button.
      ::用“ 检查” 按钮检查您的答案 。
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     Summary
    ::摘要

    When writing i nequality sentences, pay close attention to the language used:
    ::在撰写不平等判决时,要密切注意所使用的语言:

    includes  x : excludes  x : below  x : at most less than above  x : at least more than

    ::包括 x: excludes x: 低于 x: 最无比大于