Course: 3.22 计量系统间转换的估算

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计量系统间转换的估算

Sarah is staying with her aunt in London for spring break. One night they decide to make Sarah's favorite recipe for roasted Brussels sprouts. Sarah's recipe calls for $\begin{aligned} 1 \frac{1}{2} \end{aligned}$ pounds of Brussels sprouts. The grocery store uses the metric system so Sarah has to weigh her Brussels sprouts in kilograms. How can Sarah estimate the number of kilograms of Brussels sprouts to buy so that she has the correct amount for her recipe?
::Sarah在伦敦的姨妈那里过春假。一天晚上,他们决定做Sarah最喜欢的食谱, 做一个烤熟的布鲁塞尔芽。 Sarah的食谱需要12到2磅的布鲁塞尔芽。杂货店使用量子系统, Sarah不得不用公斤来称她在布鲁塞尔的芽。 Sarah如何估计布鲁塞尔芽的公斤数,以便她有正确的食谱数量?

In this concept, you will learn how to estimate equivalence between customary and metric units of measure.
::在这个概念中,你们将学会如何估计习惯计量单位和计量计量计量单位之间的等值。

Estimating Conversions Between Systems of Measure
::测量系统之间的估计转换

There are two common systems of measurement used throughout the world.
::全世界使用两种共同的计量制度。

The customary system is the system of measurement primarily used in the United States. Units in this system include the inch, foot , mile , pound, and cup .
::习惯系统是主要在美国使用的测量系统,该系统的单位包括英寸、英尺、里程、磅和杯子。

The metric system is the system of measurement primarily used in science and in countries outside of the United States. Units in this system include the meter , liter, and gram.
::衡量系统是主要用于科学和美国以外国家的测量系统,该系统的单位包括仪表、升数和克数。

Sometimes you will need to convert between the customary system and the metric system. The table below shows the approximate customary equivalent for common metric units.
::有时你需要转换习惯制和公制。下表显示了通用公制单位的近似习惯等同物。

Approximate Customary Equivalents for Common Metric Units
Metric Unit	Customary Unit
1 centimeter	0.39 inch
1 meter	3.28 feet
1 kilometer	0.62 mile
1 milliliter	0.2 teaspoon
1 liter	4.23 cups
1 gram	0.04 ounce
1 kilogram	2.2 pounds

Notice how in this table all of the metric units are given in units of 1. So, for example, since 1 meter is about 3.28 feet, to convert 2 into feet just multiply 3.28 by 2 to get 6.56 feet.
::注意这个表格中所有的计量单位是如何以1的单位表示的, 例如,1米大约是3.28英尺, 将2乘以3.28乘以2 才能达到6.56英尺。

Sometimes you will just want to get a general idea of what a metric measurement would be in the customary system of measurement or vice versa. If this is the case, you can use the table above and your estimation skills to determine an approximate equivalence.
::有时,你只想大致了解习惯计量系统中衡量标准是什么,反之亦然。如果情况如此,你可以使用上表和估算技能来确定大致等值。

Here is an example.
::举一个例子。

About how many inches is 14 ?
::14英寸多少英寸?

First, look at the table to see how inches and centimeters are related. You can see that 1 centimeter is approximately 0.39 inch.
::首先,看看桌子,看看英寸和厘米之间有什么关联。你可以看到,一厘米大约为0.39英寸。

Now, because you are going from a metric unit to a customary unit, you will need to multiply the given value by the customary equivalent from the table.
::现在,因为你正在从一个公制单位到一个习惯单位, 你需要将给定值乘以表格中的习惯等值。

\begin{aligned} 14 \times 0.39 = 5.46 \end{aligned}

The answer is there are approximately 5.46 inches in 14 centimeters.
::答案是大约14厘米内有5.46英寸。

Let's look at another example.
::让我们再举一个例子。

About how many kilograms is 7.7 pounds?
::关于多少公斤是7.7磅?

First, look at the table to see how kilograms and pounds are related. You can see that 1 kilogram is approximately 2.2 pounds.
::首先,看看这张桌子,看看公斤和磅之间的关联。你可以看到,1公斤大约是2.2磅。

Now, because you are going from a customary unit to a metric unit, you will need to divide the given value by the customary equivalent from the table.
::现在,因为你正在从一个习惯单位变成一个衡量单位,你需要将给定值除以表上的习惯等值。

\begin{aligned} 7.7 \div 2.2 = 3.5 \end{aligned}

The answer is there are approximately 3.5 kilograms in 7.7 pounds.
::答案是7.7磅,约3.5公斤。

Examples
::实例

Example 1
::例1

Earlier, you were given a problem about Sarah and her Brussels sprouts recipe.
::早些时候,你得到一个问题关于莎拉和她的布鲁塞尔芽配方。

Her recipe calls for $\begin{aligned} 1 \frac{1}{2} \end{aligned}$ pounds of Brussels sprouts but the grocery store in London uses the metric system. Sarah needs to figure out how many kilograms of Brussels sprouts to buy.
::她的食谱需要12磅的布鲁塞尔芽,但伦敦的杂货店使用公制。 Sarah需要弄清楚要买多少公斤的布鲁塞尔芽。

First, Sarah should note that 1 kilogram is approximately 2.2 pounds.
::首先,Sarah应该注意到 1公斤约2.2磅。

Now, because she is going from a customary unit to a metric unit, she will need to divide the $\begin{aligned} 1 \frac{1}{2} \end{aligned}$ pounds by the customary equivalent from the table. Sarah should keep in mind that $\begin{aligned} 1 \frac{1}{2} \end{aligned}$ is equal to 1.5.
::现在,由于她正在从一个习惯单位变成一个公制单位,她需要将12磅从表中的习惯等值除以12磅。 Sarah应该记住,12磅等于1.5磅。

\begin{aligned} 1.5 \div 2.2 \approx 0.68 \end{aligned}

The answer is Sarah should buy approximately 0.68 kilogram of Brussels sprouts.
::答案是Sarah应该购买大约0.68公斤的布鲁塞尔芽芽。

Example 2
::例2

About how many cups is 16 liters?
::关于16升的杯子有多少?

First, look at the table to see how cups and liters are related. You can see that 1 liter is approximately 4.23 cups.
::首先,看看桌子,看看杯子和升子是如何关联的。你可以看到,一升大约是4.23杯。

Now, because you are going from a metric unit to a customary unit, you will need to multiply the given value by the customary equivalent from the table. Keep in mind that 4.23 is about 4, and 16 times 4 is equal to 64.
::现在,由于您正在从一个公制单位到一个习惯单位, 您需要将给定值乘以表格中的习惯等值。记住4. 23 大约是 4, 16乘以 4 等于 64 。

\begin{aligned} 16 \times 4.23 \approx 64 \end{aligned}

The answer is there are approximately 64 cups in 16 liters.
::答案是,16升中大约有64个杯子。

Example 3
::例3

About how many grams is 0.16 ounce?
::关于多少克是0.16盎司?

First, look at the table to see how grams and ounces are related. You can see that 1 gram is approximately 0.04 ounce.
::首先,看看桌子看看克和盎司之间有什么关联。你可以看到 1克大约是0.04盎司。

\begin{aligned} 0.16 \div 0.04 = 4 \end{aligned}

The answer is there are approximately 4 grams in 0.16 ounce.
::答案是,0.16盎司中大约有4克。

Example 4
::例4

About how many kilograms is 6 pounds?
::6磅是多少公斤?

Now, because you are going from a customary unit to a metric unit, you will need to divide the given value by the customary equivalent from the table. Keep in mind that 2.2 is about 2, and 6 divided by 2 is equal to 3.
::现在,由于你正在从一个习惯单位变成一个公制单位,你需要将给定值除以表中的习惯等值。记住2.2是大约2,6除以2等于3。

\begin{aligned} 6 \div 2.2 \approx 3 \end{aligned}

The answer is there are approximately 3 kilograms in 6 pounds.
::答案是,大约6磅有3公斤。

Example 5
::例5

About how many meters is 12 feet?
::12英尺有几米长?

First, look at the table to see how meters and feet are related. You can see that 1 meter is approximately 3.28 feet.
::首先,看看桌子,看看米和脚的关联。你可以看到,1米大约是3.28英尺。

Now, because you are going from a customary unit to a metric unit, you will need to divide the given value by the customary equivalent from the table. Keep in mind that 3.28 is about 3, and 12 divided by 3 is equal to 4.
::现在,由于你正在从一个习惯单位变成一个公制单位,你需要将给定值除以表中的习惯等值。记住3.28是3,12除以3等于4。

\begin{aligned} 12 \div 3.28 \approx 4 \end{aligned}

The answer is there are approximately 4 meters in 12 feet.
::答案是12英尺有大约4米

Review
::回顾

Estimate a customary equivalent for the following metric measurements.
::估计以下衡量尺度的习惯等值。

4 kilograms to pounds
::4公斤至4公斤

7.5 meters to feet
::7.5米至英尺

6 liters to cups
::6升到杯子6升

13.25 kilometers to miles
::13.25公里到英里

6 kilometers to miles
::6公里到6英里

8 liters to cups
::8升到杯子8升

20 kilograms to pounds
::20公斤至磅

12 meters to feet
::12米到12米远

Estimate a metric equivalent for the following customary measurements, round to the nearest hundredth where necessary.
::估计以下习惯测量的计量值相当于标准值,必要时按最接近的一百分之一的四舍五入计算。

4 quarts to liters
::4 夸特至升

34 ounces to grams
::34 盎司至克

52 pounds to kilograms
::52磅到公斤

9 inches to centimeters
::9英寸至厘米

14 feet to meters
::14英尺至14米

16 cups to liters
::16个杯至升

5 miles to kilometers
::5英里至5公里

Section outline

General

计量系统间转换的估算

Estimating Conversions Between Systems of Measure ::测量系统之间的估计转换

Examples ::实例

Example 1 ::例1

Example 2 ::例2

Example 3 ::例3

Example 4 ::例4

Example 5 ::例5

Review ::回顾