Units of measurement for 11 and 12 year olds

You can read about each of them in more depth below.

Most of the questions related to units of measurement are verbal problems. In this type of problems we will receive information about some kind of unit of measurement and we will have to convert it to another one by performing a certain calculation.

If Noa walked $20$ meters, how many centimeters did she walk?

This is an example of a problem with length measurements. To answer this question we will have to convert meters to centimeters. Therefore, we will need to know the relationship between the two sizes. In this case we know that $1m=100\operatorname{cm}$.

Then we can calculate:

$20metros=20\cdot100cm=2,000\operatorname{cm}$

That is, it gave us that $20$ meters equals $2000$ centimeters. That means that Noa walked $2000\operatorname{cm}$.

With the units of measurement we measure different things or aspects. We will come across them every time we want to quantify something. For example, with measures such as meters and kilometers we can measure length. With measures such as gram, kilogram and ton we can measure weight.

Sometimes we will have a problem in which we will have to convert a certain number from one measure to another, but we will not know by heart how to do it. In these cases, within the question we will be given another piece of information or formula.

Let's look at another example:

There are different types of currencies (different monetary units) in the world. For example, some countries in the Americas use the peso, others use the dollar, and several countries in Europe use the euro.

How many cents go into $10$ dollars?

Use the exchange rate:

$1dólar=17.50$ Mexican pesos.

Solution:

First we will explain that currency conversion is a dynamic concept that is constantly changing and is affected by many economic factors. In the past the dollar was worth a different amount of pesos. Today a dollar is worth $17.50$ Mexican pesos. It is a very interesting topic, but we will not go into it in depth in this article.

Let's go back to the solution of the problem.

Recall that $1 peso = 100$ cents.

Let's calculate:

$10$$ $=10\cdot17.50pesos=175.00pesos$

$175.00$ pesos $=175\times100centavos=17500$ cents

That is, it gave us that

$10$ dollars is $17500$ cents at the current exchange rate.

Very important! During all the calculations we do, we will be careful to write down what unit it is. We will be careful not to write a number without indicating which unit it symbolizes. Remember! This is an important point that will prevent you from making mistakes in later calculations. For example, if we are calculating distance we will write down $100m$ or $100cm$ and not only $100$.

Every three-dimensional body has volume. For example, a ball or a pyramid are bodies with volume. The volume of a body is our way of measuring the place that body occupies in space.

For example, let's look at a cube that the length of each of its sides is 1 cm, like this one:

To calculate the volume of the cube we will use the known formula: length $X$ width $X$ height

In this case the three dimensions are equal and, therefore, we will write down:

$V=1\operatorname{cm}\times1\operatorname{cm}\times1\operatorname{cm}=1\operatorname{cm}^3$

V is the letter used to abbreviate the word volume in exercises and is used to designate volumes.

That is, it gave us that the volume of the cube is $1cm³$ = cubic centimeter (cm raised to the third power).

Another example - Volume:

How many liters is $10000 cm³$?

Recall that:

$1,000cm³=1litro$

Then:

$10,000\operatorname{cm}³=10\times1000\operatorname{cm}³=10\times1Litro=10Litros$

That is, he gave us that $10.000cm³$ equals $10$ liters.

Every two-dimensional body has area.

For example, every square, rectangle or circle has area. Area measures are always raised to the second power. For example: $\operatorname{cm}²$ o $m²$

Given a rectangle of length $2m\times3m$. What is the area of the rectangle at $\operatorname{cm}²$? Calculate it in two different ways.

Recall that the formula for calculating the area of a rectangle is $base\times altura$.

Solution:

Let's draw the rectangle

Let's calculate the area of the rectangle in $m²$. Many times, the letter S will represent the area:

$S=2m\times3m=6m^2$

Pay attention that we have multiplied meter by meter and, thus, we got square meters (raised to the second power).

That is to say, it gave us that the area of the rectangle is $6m²$. Only we have been asked for the area in $\operatorname{cm}²$.

We will use the formula:

$1m²=10000cm²$

In numbers:

$1m^2=10,000cm^2$

That is,

$6m^2=6\times10,000\operatorname{cm}^2=60,000\operatorname{cm}^2$

Then, the area of the rectangle expressed in $\operatorname{cm}²$ is $60,000\operatorname{cm}²$

Notice that, throughout the exercise, we have been careful to note the units of measurement and not just the numbers.

Let's draw the rectangle:

In this case we will convert the units of measurement to cm already at this stage. We know that 1 m = 100 cm. We will write it down on the rectangle:

Now let's calculate the area by multiplying the base by the height and we will get:

$A=200\operatorname{cm}\times300\operatorname{cm}=60,000cm^2$

That is, again we arrive at the area of the rectangle at $\operatorname{cm}²$ is $60,000\operatorname{cm}$.

• Length units
• Weight units
• Time units
• Currency units
• Area units
• Volume units

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What is measurement?

A comparison of dimensions based on a unit of measurement.

What is a unit of measurement?

A unit of measurement allows us to quantify the dimensions of something, with references such as length, magnitude, temperature, among others.

How many systems of units of measurement exist and what are they?

There are two known systems of units: The international system (SI) and the English system.

What are the units of measurement?

According to the SI (International System), they are universal units, classified into fundamental and derived units.

Among the fundamental units we have: length (meter), magnitude (kilogram), temperature (Kelvin degrees), time (second), electric current (Ampere), luminous intensity (Candela) and quantity of substance (Mol).

In the derived units among the most common we have: Energy (Joule), Force (Newton), Pressure (Pascal), Potential Difference (Volt), Charge (Coulomb), Resistance (Ohms).