章节大纲

  • Diving Deeper
    ::潜水深潜

    The distance between two points can be defined as the number of units between them. Typically, this means we subtract the values, but what if one point is negative and the other is positive ?
    ::两个点之间的距离可以定义为它们之间的单位数量。 通常, 这意味着我们减去数值, 但如果一个点是负的, 而另一个点是正的呢 ?

    Example
    ::示例示例示例示例

    Fatima’s friend, Tyler, is more daring than she and when he jumps into the water to scuba dive, he starts from 4 feet above the water, at the back of the boat.  After his first jump, he went 7 feet below the water. How many feet did he actually travel?
    ::法蒂玛的朋友泰勒(Tyler)比她更大胆,当他跳入水中潜水时,他从水上4英尺处开始,在船后方。 第一次跳水后,他跳到水下7英尺处。 他实际上走过几英尺?

     

     

     

     

    It is important to remember that when finding the total distance between two points on a number line , you may need to find the absolute value of those distances separately, depending on what the question is asking for. 
    ::重要的是要记住,当在数字线上找到两点之间的总距离时,你可能需要根据问题的要求,分别找到这些距离的绝对值。

     

    Along the Street
    ::沿街

    Jason lives on the same street as his school, the movie theater, his friend's house and the store. They are all different distances away from his house. Treat Jason's house as the origin, and determine the distance he needs to travel.
    ::杰森和他的学校、电影院、朋友的房子和商店都住在同一条街上,他们都离他家不远,把杰森的房子当作来源,并确定他需要旅行的距离。

     

     

     

     

    Discussion Question: Most cities are laid out in a grid pattern, where one set of streets go east/west and the second set of streets are perpendicular, running north/south. Explain to someone how to get to their destination if they can only walk along city blocks.
    ::讨论问题:大多数城市都是以网格模式划分的,其中一套街道向东/西走,第二套街道是垂直的,向北/南走,向某人解释如果他们只能沿着城区走,如何到达目的地。

     

    From the previous two interactives, you have learned that the distance between two points on the same line is the absolute value of the difference between them. So, for any two values  on a number line, a  and b ,  the distance between them is  | a − b |  .
    ::从前两次互动中,您已经了解到,同一线上两点之间的距离是它们之间的差数的绝对值。因此,对于数字线上的任何两个值,a和b,它们之间的距离是 a-b 。

     

    Getting Around   Washington DC
    ::环绕华盛顿特区

    Jason's friend, Cheryl, lives in Washington DC. Washington DC is a pretty easy city to get around in because the city is laid out in a grid pattern. All of the numbered streets run from north to south, and the lettered streets run from east to west.
    ::杰森的朋友谢丽尔住在华盛顿特区。华盛顿市是一个很容易进入的城市,因为城市以电网模式布满。所有没有数字的街道都从北向南运行,而有字母的街道则从东向西运行。

    The city is split up into 4 quadrants, Northwest (NW), Northeast (NE), Southwest (SW), and Southeast (SE). At the middle of all of these quadrants is the Capitol Building. 
    ::这个城市分为四个四人区,西北(NW),东北(NE),西南(SW)和东南(SE),在这些四人区中间是国会大厦。

    The Spy Museum is located at 9th and F NW. Cheryl is standing on the corner of 3rd and C SW. How many city blocks is she from the Spy Museum? ( Note : There are diagonal streets in Washington DC that are named after the 50 states but are not included on this map for simplicity.)
    ::间谍博物馆位于9街和F NW街交叉口。 Cheryl站在三街和C SW街的拐角处。 她来自间谍博物馆有多少个街区? (注: 华盛顿特区有以50个州命名的对角街道,但没有列入这张地图,以简单简洁。 )

     

     

     

     

       Summary
    ::摘要

    • Distance is always positive.
      ::距离总是积极的。
    • The distance between two values, a and b, on the same line is  | a − b | .
      ::同一行的两个值(a和b)之间的距离是 a-b 。
    • If two values are not on the same line, the "city block" distance is the absolute value of the difference of the x - coordinates plus the absolute value of the difference of the y - coordinates.
      ::如果两个值不是在同一行上,则“城市区块”距离是x坐标差的绝对值加上Y坐标差的绝对值。