分数四舍五入到最接近的一半

Joey is cooking and needs  $\begin{array}{r}\frac{5}{8}\end{array}$  teaspoon of pepper. He only has a one-half teaspoon measuring spoon. How many  half teaspoons of cinnamon does Joey need to make his dish? 
::Joey正在煮饭,需要58个胡椒茶匙。他只有半个茶匙量汤匙。Joey需要多少半的肉桂茶匙做饭?

In this concept, you will learn how to  round  a fraction to the nearest half.
::在这个概念中,你将学会如何将一个分数舍入到最近的一半。

Rounding Fractions to the Nearest Half
::最接近一半的人的四舍五入分数

A  fraction  is a part of a whole. Instead of finding the exact value of a fraction, you can use an estimate to get a general idea. An  estimate  is an approximate value that makes sense or is reasonable given the problem.
::分数是整体的一部分。您不能找到分数的准确值,而是可以使用估计来获得一般想法。一个估计是合理或合理的近似值,因为问题在于此。

Here is a representation of a fraction. 
::这是一小部分的表示。

[Figure 2]

There are 12 out of 20 shaded boxes. This fraction is exactly  $\begin{array}{r}\frac{12}{20}\end{array}$ . You could also say that about half of the boxes are shaded. This is called  rounding  to the nearest half.
::20个阴影箱中有12个。这个部分正好是12 20。你可以说,大约一半的阴影箱是灰色的。这叫四舍五入到最近的一半。

Think of fractions in terms of halves. There are three main values to round to when rounding a fraction to the nearest half. 
::以 一半 来思考分数 。 在四舍五入一个分数到 最近的一半时, 有三个主要值可以圆到 3 个值 。

The first is  zero . Zero is also  $\begin{array}{r}\frac{0}{2}\end{array}$ , or zero halves. The second value is  $\begin{array}{r}\frac{1}{2}\end{array}$ , or one half. The third value is 1, which can be thought of as  $\begin{array}{r}\frac{2}{2}\end{array}$ , or two halves. When rounding to the nearest half, round the fraction to whichever half the fraction is closest to on the  number line . If a fraction is equally close to two different halves, round the fraction up.
::第一个是零。 零是 0 2, 零是 0, 零是 0. 2, 零是 0. 2 。 第二个值是 12 , 或 0. 5 。 第三个值是 1 , 或 0. 2 , 或 0. 2 。 如果四舍五入到最近的 一半, 则将分数四舍五入到 一半 。 如果一个分数相等地接近两个不同的一半, 则将分数再四舍五入 。

[Figure 3]

Here is a fraction.
::这里有一个分数。

To figure out which value five-sixths is closest to, first think in terms of sixths. Since the  denominator  is six, that means that the whole is divided into six parts. The fraction  $\begin{array}{r}\frac{0}{6}\end{array}$  would be the value of zero,  $\begin{array}{r}\frac{3}{6}\end{array}$  would be the value of  $\begin{array}{r}\frac{1}{2}\end{array}$ , and  $\begin{array}{r}\frac{6}{6}\end{array}$  is the same as 1.
::要想找出六六分之五的值最接近的值, 先考虑六分之一。 因为分母是六分之一, 这意味着整个分母分为六部分。 第 0 6 分数是零, 3 6 分数是十二分之一, 6 6 分数是一分之一。

[Figure 4]

The fraction  $\begin{array}{r}\frac{5}{6}\end{array}$  is closest to  $\begin{array}{r}\frac{6}{6}\end{array}$ , so rounding to the nearest half would be rounding to 1.
::分数5 6 接近 6 6 6, 因此四舍五入到最近的一半 将四舍五入到 1 。

Examples
::实例

Example 1
::例1

Earlier, you were given a problem about Joey and his measuring spoon.
::早些时候,你被问及 乔伊和他的量子勺子的问题。

Joey needs  $\begin{array}{r}\frac{5}{8}\end{array}$  teaspoon of cinnamon but only has a  one-half teaspoon measuring spoon. Round  $\begin{array}{r}\frac{5}{8}\end{array}$  to the nearest  $\begin{array}{r}\frac{1}{2}\end{array}$  to find out how many one-half teaspoon Joey needs.
::Joey需要五十八个茶匙肉桂 但只有半个茶匙量的勺子。五十八到十二圈 才能弄清楚乔伊需要多少个半的茶匙。

Use a number line of 1 whole divided into 8 parts to round  $\begin{array}{r}\frac{5}{8}\end{array}$  to the nearest  $\begin{array}{r}\frac{1}{2}\end{array}$ .
::使用一行一号的整行,整行分为8个部分,第5轮8至最接近的12。

[Figure 5]

$\begin{array}{r}\frac{5}{8}\end{array}$  is close to  $\begin{array}{r}\frac{1}{2}\end{array}$ . Joey can use just a little over one one-half teaspoon.
::五点八分接近十二点 乔伊只需要半个茶匙

Example 2
::例2

Round the following fraction to the nearest half:  $\begin{array}{r}\frac{1}{5}\end{array}$ . 
::将以下分数舍入最近的半数:1 5。

Use a number line of 1 whole divided into 5 equal parts.  $\begin{array}{r}\frac{1}{5}\end{array}$  is closer to 0.
::使用一行一的数,将整个分为五等分。 15接近0。

[Figure 6]

$\begin{array}{r}\frac{1}{5}\end{array}$  rounds to 0.
::15发到0发

Example 3
::例3

Round the following fraction to the nearest half:  $\begin{array}{r}\frac{3}{8}\end{array}$ .  
::将以下分数四舍五入到最近的半点:3 8。

Use a number line of 1 whole divided into 8 equal part.  $\begin{array}{r}\frac{3}{8}\end{array}$  is closer to  $\begin{array}{r}\frac{1}{2}\end{array}$ .
::使用一行一的数,整数分为八等分。 3 8接近12。

$\begin{array}{r}\frac{3}{8}\end{array}$  rounds to  $\begin{array}{r}\frac{1}{2}\end{array}$ .
::3 8发子弹到12发

Example 4
::例4

Round the following fraction to the nearest half:  $\begin{array}{r}\frac{7}{9}\end{array}$ .
::将以下分数四舍五入到最近的半点:7 9。

Use a number line of 1 whole divided into 9 equal parts.  $\begin{array}{r}\frac{7}{9}\end{array}$  is closer to 1. 
::使用一行一的数行,整数分为9等分。 7 9接近1。

[Figure 8]

$\begin{array}{r}\frac{7}{9}\end{array}$  rounds to 1.
::7 9轮至1轮。

Example 5
::例5

Jessica discovered that  $\begin{array}{r}\frac{4}{9}\end{array}$  of a pan of brownies had been eaten. Is the  amount  of brownies left closer to one-half or one whole?
::杰西卡发现49块巧克力蛋糕被吃掉了

First, find the amount of brownies left. If  $\begin{array}{r}\frac{4}{9}\end{array}$  of the pan had been eaten, then that means that  $\begin{array}{r}\frac{5}{9}\end{array}$  of the pan had not been eaten.
::首先,找到剩下的巧克力蛋糕数量。如果4,9个锅被吃掉,那么这意味着5,9个锅没有被吃掉。

Then, use a number line to round  $\begin{array}{r}\frac{5}{9}\end{array}$  to the nearest half. The whole is divided into 9 parts. The fraction  $\begin{array}{r}\frac{0}{9}\end{array}$  is zero, one half is between  $\begin{array}{r}\frac{4}{9}\end{array}$  and  $\begin{array}{r}\frac{5}{9}\end{array}$ , and 1 would be  $\begin{array}{r}\frac{9}{9}\end{array}$ .
::然后,用一个数字线到 5 9 圆5 9 到 最近的 一半。 整块分为 9 个部分。 分数 0 9 是 0 零, 一半 在 4 9 和 5 9 9 之间, 1 将是 9 9 9 。

[Figure 9]

$\begin{array}{r}\frac{5}{9}\end{array}$  is closer to  $\begin{array}{r}\frac{1}{2}\end{array}$ . There was about one-half of the pan of brownies left.

::5点9分接近12点,剩下一半左右的巧克力蛋糕

Review
::回顾

Round each fraction to the nearest half.
::将每一分数四舍五入到最近的一半。

1. $\begin{array}{r}\frac{2}{15}\end{array}$
2. $\begin{array}{r}\frac{1}{7}\end{array}$
3. $\begin{array}{r}\frac{8}{9}\end{array}$
4. $\begin{array}{r}\frac{7}{15}\end{array}$
5. $\begin{array}{r}\frac{6}{13}\end{array}$
6. $\begin{array}{r}\frac{10}{11}\end{array}$
7. $\begin{array}{r}\frac{7}{8}\end{array}$
8. $\begin{array}{r}\frac{4}{7}\end{array}$
9. $\begin{array}{r}\frac{3}{7}\end{array}$
10. $\begin{array}{r}\frac{1}{19}\end{array}$
11. $\begin{array}{r}\frac{2}{10}\end{array}$
12. $\begin{array}{r}\frac{4}{5}\end{array}$
13. $\begin{array}{r}\frac{2}{3}\end{array}$
14. $\begin{array}{r}\frac{2}{11}\end{array}$
15. $\begin{array}{r}\frac{1}{9}\end{array}$

Review (Answers) 
::回顾(答复)