How to Learn Math

Math is a pretty hard subject to grasp when it doesn’t come naturally to you, but there is always a way to learn. Here are a few methods that will get you through the struggle:

  1. DO Math

Time and time again we see students come in at the last minute to study for an exam. This is not a very effective way of learning. In order to truly understand math, you have to DO it. And I don’t mean just the homework, do extra! If you didn’t understand the homework fully by the time you got to the end, that is an indication that you need to search for some extra practice. If you have a textbook, this is the easiest way to find extra practice. Typically teachers do not assign you all of the problems in a certain section. Do the unassigned problems, and if the answers aren’t at the end of the book: use Google! I promise you can always find some way to check your work. If you don’t have a textbook, search the subject plus the word “worksheet” in Google. A lot of times you’ll find something that comes up and has the answers! If all else fails, ask your teacher where you could find some extra practice. They may just provide it for you!

  1. Take Notes

I know you are thinking, well duh, but some students don’t know how to take notes in math. If you aren’t already math-minded, you may not understand just an example of a problem without explanations between steps, so write down the example with the steps in words! (If you teacher is moving too fast, ask him/her politely to slow down, trust me, other students in your class with thank you for it.) Here is an example of what I mean:

Factor: 2x^+ 4x + 2

Step 1: Look for a common factor, we see that it is 2, so divide every term by 2

2(x^+ 2x + 1)

Step 2: For trinomials with a leading coefficient of 1, we can find two numbers that multiply to the last number and add to the middle number.

1*1=1

1+1=2

Step 3: These numbers become the factors!

2(x+1)(x+1)

Personalize these to fit your needs! Experiment with different methods and find what the best one for you is. If you miss something in class, make sure to ask your teacher after class or during your lunch/study hall. And if you can: email them! They are there to help you, so take advantage of all of the time you have.

  1. Keep Organized!

It helps a lot to keep your notebook and your work organized. Keep section/chapters in order with the homework, so it is easier to look back if you are reviewing. Also, organize your work by keeping steps clear and logical. If you can’t write all of your work neatly and understandable on the worksheet provided, use extra paper! It will be easier for you to understand when looking back.

  1. Review for Tests

If your teacher does not provide a review for you, just ask! Most teachers will at least give you a list of all topics that will be on the test. Take a look back at your notes, and look back on the homeworks. Choose 4 to 5 questions from each section to practice. If you get them all correct, yay! If not, redo the whole assignment. Don’t wait until the last minute to start studying for the test. Start a week before and go section by section. This will ensure that you will have time to ask the teacher questions if you are having trouble with a certain sections.

I know that math is not an easy subject for everyone, but the best way to beat a problem is by working. Never give up, and keep pushing through, one example at a time.

Divisibility Rules

Cool Divisibility Rules

Special Thanks to: Patrick Burnett

You would probably learn the divisibility rules for 2, 3, 4, 5, 6, 8, and 9 in school. But what about the divisibility rule for 7? Well, the divisibility rule for 7 is quite simple, and quite interesting. All you have to do is take off the last digit of the number, multiply it by 2, and subtract that from the rest of the number. Here’s an example: Say you want to know if 469 is divisible by 7. If 469 is divisible by 7, then 46 – 2×9 must also be divisible by 7, and 46 – 18 = 28. Since 28 is divisible by 7, 469 is divisible by 7. That’s a quick way to check divisibility without having to do long division. Here’s another example: You want to know if 999999 is divisible by 7. If 999999 is divisible by 7, then 99999 – 2×9 = 99981 must be divisible by 7, and if 99981 is divisible by 7, then 9998 – 2×1 = 9996 must be divisible by 7, and if 9996 is divisible by 7, then 999 – 2×6 = 987 must be divisible by 7, and if 987 is divisible by 7, 98 – 2×7 = 84 must be divisible by 7, and we know that 84 is divisible by 7. Therefore, 999999 is divisible by 7.

This trick can be generalized to different numbers. For the mathematical minded: If you want to prove if a number 10X + Y is divisible by P, where X is a positive integer, and Y is an integer from 0 to 9 inclusive, and find a K such that 10K + 1 is divisible by P, then X – KY must also be divisible by P.

In layman’s terms: You know that the divisibility rule for 7 involves subtracting 2 times the last digit from the other digits. A similar trick can be applied to other odd numbers. The reason why the last digit is multiplied by 2 is because 21 is the least multiple of 7 that ends in a 1. The divisibility rule for 13 is similar, but you would have to subtract 9 times the second digit from the other digits, as 91 is the least multiple of 13 ending in a 1, and for 17, you would multiply the last digit by 5, as 51 is the least multiple of 17 ending in a 1.

Are you suspicious? I don’t blame you, but see for yourself. Multiply 17 by a large number on a calculator, and try the trick on the large number. For example, you can try 83521. 8352 – 5×1 = 8347, 834 – 5×7 = 799, 79 – 9×5 = 34, and 34 is divisible by 17, so 83521 must also be divisible by 17.

You can do this with any odd ending in 1, 3, 7, or 9, as all odds ending in these numbers will eventually have a multiple ending in 1. Try to find the divisibility rule for 97. Scroll down to see the answer when you find it.

Answer: Subtract 29 times the second digit from the first.

 

 

Repeating Decimals

The Cool Thing about Repeating Decimals

Get out your calculator and type in 331/999 and press enter. What do you get? Something along the lines of 0.331331331…? Now type in 21/9999 and press enter. What do you get? 0.002100210021…? This cool trick works with any fraction less than 1 with all nines in the denominator, which are always of the form 10A – 1, for some number A. Here’s a proof:

  • Say x = 0.A1A2A3…An…… (Where x is a repeating decimal, and A1A2A3…An is the string of numbers that is repeated in the decimal, and n is the length of the string)
  • If we multiply both sides by 10n, then we would get: x10n = A1A2A3…An.A1A2A3…An…, because the decimal point is moved n times to the right
  • x10n = A1A2A3…An.A1A2A3…An… is the same thing as A1A2A3…An + 0.A1A2A3…An, and since 0.A1A2A3…An = x, then x10n = A1A2A3…An + x
  • By subtracting both sides of the equation by x, you would get x10n – x = A1A2A3…An, or x(10n – 1) = A1A2A3…An
  • By dividing both sides by 10n – 1, you would get… x = (A1A2A3…An)/(10n – 1)
  • Therefore, by substituting 0.A1A2A3…An… for x, you would get…
  • A1A2A3…An… = (A1A2A3…An)/(10n – 1), where A1A2A3…An is a string of numbers of length n, and 10n – 1 is a string of n 9s, for example 103 – 1 = 1000 – 1 = 999

This proof is a generalization of a trick you learn in middle school. Say you want to convert 0.21… into a fraction. You would set that equal to x to get x = 0.21… and multiply both sides by 100 to get 100x = 21.21…, which is 100x = 21 + 0.21…, or 100x = 21 + x. Next you would subtract x from both sides to get 99x = 21, and x = 21/99. Don’t forget to simplify J.

Note: If you want to do something like 7/99999, add 0s in front of the 7 to make the numerator and denominator have the same number of digits to get 00007/99999, and the decimal of that would be .000070000700007…

Back-to-School Success

Tips for Students and Parents

And just like that, another summer is over and a new school year begins! Here are some tips for both parents and students to work together to ensure a successful school year.

Students

1.  Set goals: Write them out clearly and display them somewhere that you see them everyday

                ex: I will complete my HW before I watch TV

2.  Get organized: This includes finding a way to organize papers going back and forth from subject to subject.  How are you going to know what your assignments are and when they are due? 

3. Plan: What HW, tests, and quizzes do you have this week?  How will you prepare for them?  Make sure you plan out your study time.

4. Practice: This is how you learn!  Make time each day to practice.

5. Get Help: Are you not understanding what you are supposed to be learning?  Ask!  Get help!  Go to your teacher, parent, and of course, MaThCliX!  That is what we are here for.

Parents

1.  Make sure that you know how to communicate with your student’s teacher.  Know when conferences are and plan to have a presence and be proactive in your student’s academics.

2. Check grades!  Even if your student is old enough to check their own grades, it never hurts to have a parent checking, too.  Know when progress reports and report cards are due.  If you see grades dropping, intervene quickly!

3.  Make sure your student is doing the success tips for students.  Ask them how they are doing each one.

4.  Find out about what student’s are learning each week so that you can help or get help, as needed.  Find out about tutorials, teacher websites, and recommended resources.

5. Bring your student to MaThCliX! 

Join Math Team

You may be discouraged from joining the math team because you don’t think you’re not good at it, but like many other things in life, you can get better at math by working hard at it and with the proper attitude. All you need is a love of math, the desire to make yourself better, and a winning attitude. If you don’t like math, then maybe joining math team can change your opinion on math. At math competitions, you commonly get problems that require you to think outside the box and think of creative solutions, unlike traditional high school math. If you are interested or just want to try it out, talk to your school’s math team coach and ask him or her about joining the team. He or she would be more than willing to help you out. If your school doesn’t have a team and you want to start one, take initiative and find a teacher who is willing to sponsor and coach a math team. There are lots of math competitions in Georgia every year, where you get a chance at showing off your math skills, finding opportunities to improve, and simply having fun. If you see a problem you don’t understand, don’t feel discouraged. If you are willing to learn the tricks, you will get better and better at it, and eventually, if you do consistently well at math competitions, you can make it on one of Georgia’s state ARML teams, where the best are selected from all over Georgia to compete in a competition involving teams from all over the US and even from other countries, like Colombia and China. You get to interact with kids who love math just like you from all over Georgia and stay at a dorm at the University of Georgia to #DoMaTh and/or socialize with the kids and compete for a chance for fun and international glory.

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