# SBP-Program

## Natural numbers

### Natural numbers definition

Natural numbers definition:

Natural numbers are positive whole numbers.

Natural numbers are used for counting objects and many other purposes.

The N symbol is usually used to denote the set of natural numbers.

### Example of natural numbers in algebra

The example of natural numbers in algebra:

1; 2; 3; 4;...

### Example of natural numbers in real life

The example of natural numbers in real life:

one person
two cats
three houses
four trees
five stars

In the example above, the one, two, three, four, five are natural numbers. Here we used them for counting.

### Is zero a natural number or not?

Is zero a natural number or not? No, it is not. Why not? Because we use natural numbers for counting. We always count so:

one cat, two cats, three cats...

And we do never count so:

zero cat, one cat, two cats...

Natural numbers are positive integers and zero is not a natural number.

### How many natural numbers are there?

How many natural numbers are there? There is an endless amount of natural numbers.

### What is the smallest natural number?

What is the smallest natural number? The smallest natural number is one.

### What is the largest natural number?

What is the largest natural number? The largest natural number is unknown. There is an endless amount of natural numbers and we cannot indicate the largest number.

### Sum of natural numbers

The sum of natural numbers is always a natural number.

Example. Here a and b are two natural numbers:

a + b = c
(here c is a natural number)

### Product of two natural numbers

The product of two natural numbers is always a natural number.

Example. Here a and b are two natural numbers:

a * b = c
(here c is a natural number)

### Difference of two natural numbers

The difference of natural numbers is not always a natural number.

The difference of natural numbers is a natural number if the minuend is greater than the subtrahend.

Example. Here a and b are two natural numbers and a > b:

a - b = c
(here c is a natural number)

Example. Here a and b are two natural numbers and a <= b:

a - b = c
(here c is not a natural number)