The location of whole numbers and decimals is delimited by a comma, also called a decimal point. The integer part of a real number is written to the left of the comma while the decimal part of the number is written to the right.
The universal notation to write a number with an integer part and a decimal part is to separate these parts with a comma, but there are places where they use a period.
In the previous image we can see that the integer part of one of the real numbers is 21, while the decimal part is 735.
Location of the integer part and the decimal part
It has already been described that when a real number is written, the notation used to separate its integer part from its decimal part is a comma, with which we will know how to locate each part of the given number.
Now, just as the whole part is divided into units, tens, hundreds and more, the decimal part is also divided into the following parts:
- Tenth s: is the first number to the right of the comma.
- Hundredths: is the second number to the right of the comma.
- Thousandth s: is the third number to the left of the comma.
Therefore, the number in the image at the beginning is read as "21 735 thousandths."
A well-known fact is that when a number is an integer, the zeros added to the left of that number do not affect its value, that is, the numbers 57 and 0000057 represent the same value.
As for the decimal part, something similar happens, with the difference that the zeros must be added to the right so that they do not affect its value, for example, the numbers 21,735 and 21,73500 are actually the same number.
With what has been said above, it can be concluded that the decimal part of any whole number is zero.
The real straight
On the other hand, when the real line is drawn, it begins by drawing a horizontal line, then in the center the value zero is placed and to the right of the zero a value is marked to which the value of 1 is assigned.
The distance between two consecutive integers is always 1. Therefore, if we place them on the real line, we will obtain a graph like the following one.
At first glance you can believe that between two integers there are no real numbers, but the truth is that there are infinite real numbers which are divided into rational and irrational numbers.
The rational and irrational numbers located between the integers n and n + 1, have an integer part equal to n, while their decimal part varies along the entire line.
For example, if you want to locate the number 3,4 on the real line, you first locate where 3 and 4 are. Now, divide this line segment into 10 parts of equal length. Each segment will have a length of 1/10 = 0.1.
Since the number 3,4 is to be located, 4 segments of length 0.1 are counted to the right of the number 3.
Integers and decimals are used almost everywhere, from the measurements of an object to the price of a product in a warehouse.
References
- Almaguer, G. (2002). Mathematics 1. Editorial Limusa.
- Camargo, L., Garcia, G., Leguizamón, C., Samper, C., & Serrano, C. (2005). Alpha 7 with standards. Editorial Norma.
- EDITORIAL, FP (2014). MATH 7: Mathematical Reform Costa Rica. F Prima Editorial Group.
- Higher Institute of Teacher Training (Spain), JL (2004). Numbers, shapes and volumes in the child's environment. Ministry of Education.
- Rica, EG (2014). MATH 8: A Problem-Based Approach. Editorial Grupo Fénix.
- Soto, ML (2003). Reinforcement of Mathematics for curricular support and diversification: for curricular support and diversification (illustrated ed.). Narcea Editions.