Lesson 1: Factors and Multiples

Math 10C Module 2 Lesson 1

Module 2: Roots and Powers

Lesson Assessment

Complete the lesson quiz posted under the Assess tab or by using the Quizzes link under the Activities block. Also, ensure your work in your binder (course folder) is complete.

Project Connection NOT ASSIGNED

Prime numbers play an important role in the creation of secret codes. Some of the most difficult codes to break in the world are based on very large prime numbers. The reason why these codes are tough to break is because there is no quick way to find the prime factors of large numbers. Even modern methods that are used to determine prime factors of large numbers are little better than the brute force method of checking all divisors. In fact, it could take hundreds of years to compute the prime factorization of a thousand-digit number!

Here is an opportunity for you to crack a secret code. In the Discover section of this lesson, you used a chart to determine all the prime numbers less than 100.

Use this chart to uncover a hidden message in the poem:

A green auto

Toward our parking bay

Covered up by bark

From a reeking tree

Towed phoenix sandwiches

Outlandishly by Emma.

For hints, check with your teacher.

At this time, go to the Unit 2 Project and complete the Module 2: Lesson 1 portion of the project.

Going Beyond

This shows a photo of a World War 2 enigma cipher coding machine.

shutterstock

Codes have long been used to relay messages. In the days of the Cold War, agents from opposing nations tried to prevent enemies from learning military secrets through the use of spy codes.

Today, secret codes continue to be used not only by the military but also by ordinary citizens. Every time you access your online bank account or make an online purchase, you may need to enter a password or code to gain access to private information. There is a whole industry that has evolved that looks strictly at protecting this information. At the same time, criminals continue to develop sophisticated ways of penetrating these security measures and stealing personal information.

Cryptography is the process of storing information in a form that appears scrambled. The original message, known as plaintext, is scrambled using an encryption engine. The engine takes this plaintext and applies information based on prime numbers to create the scrambled message that is called ciphertext. To unscramble the ciphertext, the recipient needs to have access to the key and decryption software.

Did You Know?

People have always been interested in keeping secrets. Children’s author Beatrix Potter kept a diary that was written in code. She maintained the belief that the diary would never be read!