Section outline

  • How can you add and subtract decimals with blocks?
    ::您如何用区块添加和减去小数点 ?

    lesson content
    Adding and Subtracting Decimals

    Create decimal values using the blocks in the interactive. Try adding the values together and subtracting decimal values using the blocks. Later in this lesson, you will add and subtract decimal values numerically but you can always come back to this interactive with the blocks if you need to.
    ::使用互动中的区块创建小数点值。尝试将数值加在一起,并使用区块减去小数点值。在此课后,您将用数字方式添加和减去小数点值,但如果需要,您总是可以返回到与区块互动的区块中。

    INTERACTIVE
    Adding Decimals with Blocks
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    • Drag the blocks to add together decimals.
      ::拖曳区块以将小数点组合起来。
    • Click the blocks to subtract decimals.
      ::单击各个区块以减小数。
    • Press the reset button to clear the blocks from the screen.
      ::按重设按钮清除屏幕上的块 。
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    Use the interactive to practice adding these decimals:
    ::使用交互操作来练习添加这些小数:

    0.45 + 3.66 =
    ::0.45 + 3.66 = 输入您的答复

    4.99 + 0.59 =
    ::4.99 + 0.59 = 输入您的答复

    1.01 + 0.99 =
    ::1.01 + 0.99 = 输入您的答复

    3.33 + 0.88 =
    ::3.33 + 0.88 = 输入回答

    CK-12 Widget Interactives
    ::CK-12 部件互动

    Try adding together decimal values using the interactives below.
    ::尝试使用下面的交互效果将小数点值合并到一起 。

    After you press "Try It," notice how the decimal values are lined up.
    ::按下“尝试它”后,请注意小数点值的排列方式。

    In these more complex problems , you will have to " carry over" a 1 when  adding the two decimal values. 
    ::在这些更为复杂的问题中,在添加小数点后两个值时,您必须“携带”一个 1。

    How much horsepower do toy cars have?
    ::玩具车有多少马力?

    lesson content
    RC Car

    You can use horsepower to measure the power of a car engine. A regular family car has about 120 horsepower. A race car has 750 horsepower or higher. 
    ::您可以使用马力测量汽车发动机的功率。普通家庭汽车拥有120匹马力。赛马汽车拥有750匹或以上的马力。

    In the interactive below, find the remote control car with the most horsepower by changing the speed for each car and comparing their horsepower.
    ::在下文互动中,通过改变每辆汽车的速度和比较其马力,找到最有马力的遥控车。

    INTERACTIVE
    Toy Car Horsepower
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    • Drag the red slider to change the speed settings of the car.
      ::拖动红色滑块以更改汽车的速度设置。
    • Click the buttons to switch cars and make it move.
      ::单击按钮以切换汽车并让它移动。
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    CK-12 Widget Interactives
    ::CK-12 部件互动

    Try subtracting decimal values using the interactives below.
    ::尝试用下面的交互效果来减减小数数值 。

    In the more advanced problems below, you will have to "borrow" when subtracting the two decimal values.
    ::在下面更先进的问题中,在减去两个小数点后,您必须“借款” 。

    How fast can a robot solve a Rubik's cube?
    ::机器人能用多快解开魔方?

    lesson content
    Rubik's Cube

    The Rubik's cube is a 3D puzzle that people try to solve with a series of turns until each face of the cube is only one color. Try mixing up a Rubik's cube in the interactive below.
    ::魔方是一个 3D 的拼图, 人们尝试用一系列的转折来解答它, 直到魔方的每个面部只有一个颜色。 尝试在下面交互的框中混合一个魔方 。

    INTERACTIVE
    Rubik's Cube
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    • Toggle the axis with the buttons at the bottom of the interactive. 
      ::在互动的底部切换按键轴。
    • Use the rotate buttons to move the Rubik's Cube rows and columns.
      ::使用旋转按钮移动魔方的立方体行和列。
    • The rows and columns move by 180º when the rotate buttons are used.
      ::使用旋转按钮时,行和列移动180o。
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    The two fastest solve times for a Rubik's cube  came from robots.
    ::魔方两个最快的解答时间来自机器人

    Robot  1 solve time: 0.38 seconds
    ::机器人 1 解答时间: 0.38秒

    Robot 2 solve  time: 0.637 seconds
    ::机器人 2 解答时间: 0. 637秒

    How much faster is the first robot at solving the Rubik's cube than the second robot? Use the interactive below to find out.
    ::解决魔方的第一个机器人比第二个机器人快多少? 使用下面的交互操作来找出答案。

    How far do the snails crawl?
    ::蜗牛爬多远?

    lesson content
    Snail Trail

    When snails crawl, they leave behind a visible path. You can compare the distance that two snails crawl by measuring these trails. 
    ::当蜗牛爬行时,它们留下一条可见的路径。您可以通过测量这两只蜗牛爬行的距离来比较这两只蜗牛爬行的距离。

    In the interactive below, drag the snail across the measurements to gets its distance. As you use interactive, think about how you would add and subtract the distances traveled by the two snails.
    ::在下面交互的空格中, 拖动蜗牛通过测量获得距离。 当您使用交互时, 想想如何添加和减去这两只蜗牛的距离 。

    INTERACTIVE
    Snail Stroll: Decimal Rounding Given Place Value
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    Charlene notices the snails in her backyard. They leave a slimy, white trail wherever they go. She uses a ruler to measure the distance of each trail.
    ::Charlene注意到后院的蜗牛,不管他们走到哪里,都留下一条粘糊糊的白色痕迹,她用尺子测量每一条痕迹的距离。

    • Use the red points to drag the snails and create white trails.
      ::使用红点拖曳蜗牛并创建白色足迹。
    • The white trail lengths are displayed behind each snail.
      ::每只蜗牛后面都显示白色的足迹长度。
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      Summary
    • When adding and subtracting decimals using the standard method, line up the numbers vertically by the decimal points.
      ::在使用标准方法增减小数时,用小数点垂直排列数字。