Introduction


 * Introduction: Welcome to Subtraction Mission (Im)Possible! ﻿**

media type="file" key="SubtractionMissionIntroduction.mp3" width="240" height="20" (Click here to listen to the text of this lesson.)

Congratulations! You have been selected among thousands of applicants as a possible candidate to train as a special agent for subtraction missions. You have been selected for your remarkable potential as a thinker and risk-taker. However, before reaching the status of “special agent for subtraction”, you have to go through intensive training. To qualify and pass the ultimate test as a special agent, you have to be able to do the following:

** Subtract a two-digit number from another two-digit number. **

** Pre-Assessment: ** Before you can embark on the training mission, your Mission Leader needs to check whether you have any prior knowledge. Download the pre-assessment and complete it. Save it to your computer. Use your name and the word pre-assessment to name the document. Forward it by email to the Mission Leader (i.e. your teacher).



Are you ready to find out more about this training mission? The training mission consists of seven different tasks and will introduce you to numerous secret weapons needed in solving subtraction problems:

** Lesson 1: ** Would you recognize subtraction if it looked you in the eye? ** Lesson 2: ** Preparing for Mission (Im)Possible ** Lesson 3: ** Reaching a cross-road – which path to take? ** Lesson 4: ** Trick or trade! ** Lesson 5: ** Mission (Im)Possible… Subtract! ** Lesson 6: ** Mission completed? Don’t be deceived? ** Lesson 7: ** Agent X, are you ready for the ultimate challenge?

You have to work through each in this order. For each successful completion, you will be awarded a star on your special agent badge. (You can find the agent badge at the back of your personal mission notebook).

Before you can begin, you have to meet the other two key players in this mission: **Mr. Minuend** and **Mrs. Subtrahend**. Watch the following video to get familiar with them because the success of your training and mission will depend on your ability to keep them apart.

media type="youtube" key="T2bmpBcE8_U" height="349" width="560"

So, the minuend (aka Mr. Minuend) is the number from which the subtrahend (aka Mrs. Subtrahend) is taken away.

There is just one more thing you need to do before you can get started: read through the following important tips on how to work best on the instruction.

** Tips & tricks for a successful mission: **
 * Special agents need to work under cover in a hidden location – find a quiet spot where you can work on these secret documents.
 * Special agents need much focus and concentration – make sure that there is nothing around you that might distract you.
 * Special agents need to work time-efficiently – keep a watch. Try not to work longer than 30min on each lesson.
 * Special agents need to be diligent record keepers – make sure that you save all completed worksheets in a folder (Subtraction Mission Possible) on your computer and where applicable in your Mission Notebook.
 * Special agents need to follow directions from the Mission Leader (i.e. your teacher) precisely – follow the directions and work on the lessons in the order they are given, starting with Lesson 1 and ending with Lesson 7.
 * Special agents need to work responsibly on their mission – make time every second day to work on the tasks until the mission is completed.

** Good luck! **

Click here to go to Lesson 1