1. Centuries (Siglos)
By: Mrs. Santiago

2. Time in history is usually measured in centuries.

3. Centuries
A century is a one hundred year period.
100 years!!!!

4. Centuries are usually written in ordinal numerals.

5. Ordinal numerals???
Ordinal numerals are numbers that denote sequence, similar to the natural numbers, which you already know.
For example: Centruy 21 is written 21st century.

6. Ordinal numerals
Sometimes, instead of saying, “The film camera was invented in 1888.” we may say, “The film camera was invented in the 19th century”.

7. Ordinal numerals But how do you know how to speak about centuries?
Given a four-digit year (for example) 2008), take the first two digits (20) and add one unit ( = 21).
Thus, you know that 2008 belongs to the 21st century.
For years with three digits (such as 320), take the first digit (3) and add one unit, (3 + 1 = 4). The year 320 is in the 4th century.

8. That means, that the 2018 year belongs to the 21 century!
Lets practice!!!
2018 belongs to the __________ century.
think!…..think!…..think!.....think!.....think!.... 20
think!…..think!…..think!.....think!.....think!....
think!…..think!…..think!.....think!.....think!....
think!…..think!…..think!.....think!.....think!....
+ 1 = 21
That means, that the 2018 year belongs to the 21 century!

9. When begin and end a century???
A century always begin in number cero, and ends with a number 9.
Example:
The 4th century, begins in the 300 year and ends in the 399 years.
The 21st century, begins in the 2000 year and ends in the 2099.
GOT IT??? Weeeeeeeeeeeeeee!