Skip to main content

Guess the Number

Guess the secret number like a Magician, or even better like Mathematician!

So, what are the rules of this game? 

In order to play this game you will need a partner, someone from your family or a friend. You can ask them to think of a number, their secret number, which will be your goal to guess. 

After that, ask them to:

Subtract 11

Add  2

Aaaand, then they should tell you the result the have got.

 So, let's say they have got 5. What should you do to find out the mysterious number?

Credit: http://clipart-library.com/magic-hat.html

The "secret recipe" is to Work backward to find the original number: 😉

We should start with the 5, then apply every opposite operation of the stated one. So, opposite of addition is subtraction, hence, we should do
 5 -2, which equals 3, 
then taking that (5-2) and instead of subtraction, again applying the opposite operation, we are going to do addition, we will get
(5-2)+11=14,
 and voilà, the number that you need is 14. 
You can tell your partner the number, and I believe he /she will be super-surprised by your magical skills, which are actually mathematical skills 😊
Credit:Bitmoji App

The Math Behind 

This is an example of a grade 7 problem, when the students are working on the concepts of Operations with Integers. 

But, absolutely we can make it to a G4-level, just using smaller numbers, where the students will be able to do the math by using only logical reasoning, since they haven't learned the theory of negative numbers. Or, even G11-level, if we add some exponents, or maybe irrational numbers, logarithm's conditions and so on.

Let's present the Math behind the example given above.

This is nothing more than solving an (in this case linear) equation with one variable, let's denote x. 

(x-11)+2=14 

x-11+2=14 

x+9=14, 

x=14-9 

x=5 

As you can see, math can be hiding anywhere around us 😊 Even in a wizard's hat 🧙



Comments

Post a Comment

Popular posts from this blog

Bedtime Math- book review

In the series of Books Bedtime Math, by author Laura Overdeck, we get familiar some fun facts 😀 There are four Bedtime Math books: Bedtime Math: A Fun Excuse to Stay Up Late Bedtime Math: This Time It’s Personal Bedtime Math: The Truth Comes Out Bedtime Math: How Many Guinea Pigs Can Fit on a Plane? I read two of them, for which I'm going to share my personal impression.      The first book that I read was the Bedtime Math: The Truth Comes Out. That books consists of 40 fun facts fitted into paragraph-long texts. Besides the facts, on the next side (one title covers two pages) you can see math-related questions on three levels of understanding math + the bonus question. The questions range from pre-K up to G7 maybe, although some bonus-problems are really tricky. I learned nice fun facts. The most interesting for me was the "Staring Contest", where the author is sharing the fact the camels have a 3 eyelids! Wow! Isn't that weird? 😀  To summarize, this book is fun-...
1 comment
Read more

My May's List of Read Books- Just One!!

I need more time to read!!! I really do! As current student (yeah teachers can be students as well) at the Vancouver School Board, Adult Education, taking the English Studies 12, I have almost no time for literature and focus that can be placed at additional reading. Howeveeeer, I have put a lot of effort in managing my time; being student, being a math tutor, being wife and support to my husband, and being aunt (daily checking up my baby nephew).  But, (and yes, my English teacher said that we are not supposed to start our sentences with "but", but there are some tendencies in moving from that point, so I'm just gonna slide toward these tendencies haha by starting my sentences with "but", "so", and "and"), where was I... oh yes, so, here I am, proud to announce that I read a book, and even more, I'm gonna write a vlog stating my opinion on it! Ha! So, let's see. 😀 What's the point of Math?   This cute math's book's autho...
1 comment
Read more

Is there any chance...?

  One quote that caught my attention from the book Student Engagement Techniques by Elizabeth Barkley and Claire Howell Major (2020) is: “Students must have confidence that, with appropriate effort, they can succeed. If there is no hope, there is no motivation” (p. 20). Although hope was the last thing left in Pandora’s box, the authors suggest that for students, hope is the first condition for success. Without it, motivation cannot exist. This quote comes from Chapter 2, “Engagement and Motivation.” I came across couple of strong candidates for my reflection from both Chapters 1 and Chapter 2. One idea I found particularly intriguing as a mathematician is what I like to call the ‘zero-product property,’ where the authors emphasize that it's about the product, not the sum. However, after reading the quote: “Students must have confidence that, with appropriate effort, they can succeed. If there is no hope, there is no motivation” (Barkley & Major, 2020, p. 20)—I immediately sto...
1 comment
Read more