Digits and Numbers

Table of contents
Definitions
  • A digit is a symbol used to represent numbers.

  • A number is a mathematical concept used to count, evaluate, measure, compare or order quantities.

Tip

How can we avoid confusing the words numbers and digits?

A number is comparable to a word, whereas a digit is comparable to a letter. In other words, numbers are composed of digits in the same way as words are composed of letters.

The following symbols are used to represent the ten digits of the currently used Indo-Arabic system. These digits are used to write an infinite number of numbers.

The digits

 0 

zero

 

 5 

five

Visual representation of the number 5.

 1 

one

Visual representation of the number 1.

 6 

six

Visual representation of the number 6.

 2 

two

Visual representation of the number 2.

 7 

seven

Visual representation of the number 7.

 3 

three

Visual representation of the number 3.

 8 

eight

Visual representation of the number 8.

 4 

four

Visual representation of the number 4.

 9 

nine

Visual representation of the number 9.
Examples
  • The number |6| represents the number of stars inside the following set.

A set that contains 6 stars.
  • The number |-2| is represented by the position of point |A| on the number line.

The number -2 on a number line.
  • The number |72.95| represents the price of this pair of shoes in dollars.

The price of a pair of shoes is $72.95.

There are several ways to write numbers. The most common numbering system uses Arabic numerals and decimal notation. However, there are other numbering systems, such as Roman numerals. There are also several other notations for numbers, such as fractional notation, exponential notation, etc.

Since each digit in a number occupies a position that determines its value, it is possible to decompose the numbers to order them in ascending or descending order.

Numbers can also be grouped into different number sets according to their characteristics.

Finally, it is important to know the rules of agreement and writing numbers.

Exercise

Exercise

Digits and Numbers

Mathematics Secondary1