1. Day 143 Number theory with Closure (day 1)

2. Introduction
In day to day life, we use numbers in calculation, in quantifying items, measuring and, so on. These numbers vary and there is need to understand their nature so as to work with correctly. In this lesson, we are going to look the closure property of natural numbers and integers.

3. Vocabulary: Natural numbers
They are counting numbers, example, 1,2,3,4,…
Closure
The a description of a situation where an operation on numbers of the same category gives rise to number of the same category as the first ones
Integers
They are composed of natural numbers, their negatives and zero. Example 1, 3, -4, -12, 0, …
This can be done in the notebooks or on vocabulary cards. Whatever system you use 

4. Natural Numbers
These are counting numbers. They include 1,2,3,…
Closure of Natural numbers
They are closed under addition and multiplication only.
Integers
They are composed of natural numbers, their negatives and zero. They include 2, -6, 0, -4, 7, …

5. Closure of integers
Integers are closed under addition, multiplication and subtraction.
Example
Write two cases showing that integers are not closed under division but they are closed under multiplication.

10. homework
Natural numbers are closed under division. Criticize or ratify the statement using an example.

11. Answers to the homework

12. THE END