Mini-Class: "Fundamental Quantities, Their Units, And How To Solve Mental Arithmetic".

The objective of mental arithmetic is to familiarize our kids and adults who are not mathematics-inclined with some arithmetic problems and solutions to such problems. As the name implies, these arithmetic problems are to be solved with our minds, without our use of pen and paper or calculator.

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Solving arithmetic problems with our minds may seem impossible, but it's not; it all depends on how familiar we are with the fundamental units or international system of units ( SI), and their conversation. For example, we may be given a problem that has to do with the measurement of mass in grams, and we are told to give a solution in kilograms; how do we do this? Simply convert your answer in grams to kilograms. Therefore, this post is to familiarize you with these basic arithmetic problems, and it would be sequential.

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Fundamental Quantities And Their Units

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The name Fundamental conveys the idea of being independent. Therefore, fundamental quantities are independent, but they are not derived. We have very few of these quantities. In your primary education, you only need to know about the fundamental quantities, but in secondary education or high school, you also need to know derived quantities, which, as the name implies, are derived from the combination of at least two fundamental quantities. Now let's get to know fundamental quantities and their units:

(1) Mass: This is a physical fundamental quantity that we use in measurement. For example, rice, beans, and things like that are measured in mass. Mass in itself is the amount of matter possessed by a body or an object.

Note: Mass and weight are two different quantities. We had earlier defined mass, which, on the contrary, weight is the gravitational force that a body possesses.

The (SI) unit of mass is the kilogram(kg), but in primary and secondary or high school education, problems in other units of mass such as gram(g) and milligram may be given to you, but to give your solution in kilogram
s. The table below will help you;

Kilogram	gram	milligram
1	1000	1000000

As seen in the table, 1000 grams equals 1 kilogram, and 1000000 milligrams equals 1 kilogram.

Note: In the university, units such as pounds, Tons, and Slugs are used in measuring mass for industrial purposes.

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(2) Length: This is the distance between two positions. Its unit is Meter. In your primary education, other units of length can be used to give you arithmetic problems, units such as centimeters, decimeters, and millimeters; then, you will be asked to give solutions in meters. The table below will help you;

Meter	centimeters	decimeter	millimeters
1	100	10	1000

Note: In university Education, other units of length such as Inch, Foot, Yard, etc are used for industrial purposes

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(3) Time: The approved unit we used in measuring time in seconds. And as we know, 60 seconds equals 1 minute, and 60 minutes equals 1 hour. You may be given a problem in minutes or hours, but you are asked to give a solution in seconds.

Days, weeks, months, years, etc, are other units of time.

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(4) Temperature: In school, we are taught that temperature is the degree of hotness and coolness of a body, and this definition still stands. Its unit is kelvin. In school, you may be given a problem in Celsius (°c) and Fahrenheit, and then you are told to give a solution in Kelvin. The table below will help you;

Kelvin	°Celsius	°Fahrenheit
273.15	0	32

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Other fundamental quantities are Current, amount of a substance, luminous intensity, and plane angle, which are measured in Ampere, Mole, Candelas, and radians, respectively.

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Some Mental Arithmetic Problems And Their Solutions

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(1) Give your answer in centimeters, 3/10 of half a meter.

Solution: referring to the table we gave under Length as a fundamental unit;

1 meter = 100 centimeters
Therefore half a meter = 50 centimeters
3/10×50 = 15 centimeters

Ans: 15cm

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(2) One carton of biscuits weighs 1 pound (p); 5 cartons of biscuits will weigh how many kilograms (kg)?

Solution:

1 pound = 0.454 kg

Since one carton of biscuits weighs 1 pound,
5 cartons = 1×5 = 5 pounds

Leaving our answer in kg:

1 pound = 0.454 kg
5 pounds = 0.454×5 = 2.27 kg

Ans: 2.27kg.

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We apply the same format to solving problems involving Temperature and other fundamental quantities. It is all about knowing the SI units of these fundamental quantities and how to convert other units to these approved units.

This is how far we can go in this session of our mini-class, and I believe you have learned something. Thanks for reading and learning.