Interest

INTEREST!

Interest is the money you pay back when you borrow money from the bank.

Its basically a formula of Principal x Rate x Time

Say that the Interest rate was at an annual rate of 8%

If you took out $100 for one year, it would be 1 (time) x 0.08 (rate) x $100 (Principal) which would equal $8 so you would have to pay $108 back to the bank for borrowing money instead of only $100

Now lets say you took out $500 for 8 years, that would make the formula...

8 (time) x 0.08 (rate) x $500 which would equal $320 that you would need to pay back

A way that you can remember the formula is by using letters...

P = Principal

R = Rate

T = Time

I = Interest

A way that I use to remember the letters is PRTI reminds me of party so I just think of an INTERESTing party:D works for me, thought it might help you during your next test.

Percent CHALLENGE!

Solve the following percent problem and post your answer as a comment. Be sure to explain all your steps!

Kora and Micah have lunch together. When the bill comes, Kora wants to leave 15% of the bill as a tip. Micah wants to leave 77¢ more, making the tip 20% of the bill. Calculate the amount of the original bill without the tip. Express your answer to the nearest cent.

Review of Percent

Hey everyone , I’m going to be talking about percentage, basically this is a review of things.

I am now going to show you three different ways of how to get a percent.

First way: 20% of 10 = __ * First of all, I will tell you, that “of” always means multiply (in math language). How to do that problem its fairly simple, all you have to do is put a decimal in front of the two. (You don’t need to put the 0) Then you put the multiplication sign and then put 10, because the question was 20% of 10 = __.

Second way: ___ % of 25 = 15 *This equation is different then the one I just showed you, but I do see something in this equation that sticks out to me which is “of” so that kind of makes it a little bit easier. What you have to do with that equation is cross multiply. You take x à (which means a known number), and put it out of hundred. Why you do that is because your trying to find the percent, and percent is always out of hundred that’s why you put the hundred bellow and why you put the x is because you don’t know what the number is. Then you just put fifteen over twenty five, because twenty five is what its multiplying out of and 15 is the answer. Next your cross multiply, so 15 times 100, and 20 times x. So 1500 = 20x then you divide 1500 and 20x, and you should get 60%.

Third way: 20% of __ =15 * This equation is not that different then the one I just showed you. The only thing that is different is that the x (un known number) is in a different place. Other wise everything is the same.

x = 75

Way to go, 8Z!

I knew you guys could do it. I'm seeing some "community" being built here. The comments are awesome - it's great when we compliment and respond to each other in positive ways. Remember it's OK to also add to the conversation if you feel that you have comments/information to add. Keep things math-related, of course.

I was encouraged when I checked my box this morning and saw so many messages. We're headed down the right road now....keep it up!!

Percentages The Real Deal

Hello my friends! I am the real Chuck Norris...Chuck Norris 101. Anyways I am going to talk about percentages. Incase you did not already know, which you now will, the word percentage actually means "per hundred", literally. So every percent is always over 100. Now remember, it is possible to have more than 100 as your numerator, for examlpe, 113/100. Now of coarse your going to want an explanation. Lets say you have an upcoming French test and the total mark of the test is out of 50. There is one bonus question on the test worth 5 marks. Lets say in this case your mark, not including the bonus is 50/50. If you get the bonus correct you will have 55/50. That is more than 100%, that is actually 110%!!! Wow!!! Good job on your French test!!!

Next I will teach you how to reduce a percent to its lowest terms.

ex. 60%= 60/100 now divide both numbers by a common denominator, in this case 2,5 and 10. lets say we reduce/divide the fraction by 10. The fraction is then 6/10 but we are not done yet, ha, thought I forgot to reduce it again, eh! Now we can reduce by 2. That would make the fraction 3/5 and now you have reached its lowest terms.

Now, we know that percent literally means "per hundred". Now think as "of" meaning "multiply". Also with the "/" meaning divide. Using these three terms you will know how to find a percent out of a whole number.

ex. 1. 75% of 40= 30

We know this because 75% is really 75/100. Now we divide 75 into 100. That will give us 0.75. Now multiply 0.75 by 40. That gives us 30.

ex. 2. When it comes to finding a percent out of a fraction, we also use these terms.

2/5=?% First you divide 2 into 5, that gives us 0.4. Then you multiply 0.4 and 100, that gives us 40.



That's right Jimmy more than 100% of your best!!! It is possible!!! Common, where did you learn that, girl scout camp!!!




















See, even Bob here got higher
than 100%. It is possible!!!

= 4/6 = 2/3 Find the percentage of 2/3.

2 divided by 3, multiply 100 = 67%

"Pizza's here, unfortunately I

ate half of a slice... ok, maybe a little more than half.

Anyways, I hope you liked my post! Most importantly I hope you learned a few things! Like not to trust pizza guy's and of coarse to learn a few things about percentages! Thanks for reading my post and I will see you soon!

CHUCK NORRIS 101 (the real Chuck Norris)

Percentage...and don't you forget it.

Hello everybody!! How are you doing? It is I, Robonorris, which is of course, if you did not know, Robotron mixed with Chuck Norris. Speaking of mixing, here is a quick riddle for you to break the ice. Okay, what do you get when you mix an owl with a bungi chord??... oh yes, I know all of you are dying of anticipation to here the answer, you get a bear. *drumroll*...ouch, tough croud.

Anyway, enough fun and games, it's time to get down to business. Our latest lesson was on the lovely topic of percentage. Per cent literally means 'for every hundred', so it is the means of calculating the number of a certain thing out of a hundred things with similar relations. In many ways, percentages are a lot like ratios, because most of the time they are comparing multiple numbers. Example: You have a collection of 100 marbles, 25 of them are blue. 25% (%=out of 100 or per cent) of your marbles are blue.

Unfortunately, if finding a percent was always just counting up something that had a denominator of 100 everytime, we wouldn't have to be learning this in school. For on almost every occassion, the grand total is not going to be 100. Sometimes there will be less, and sometimes there will be more. Here is where a formula comes in. Here is the best way how to find what the percent is in a part of a whole thing. I will use an example to help. Chuck Norris throws a party, and invites 5 guests. There were five guests and one of him, making a grand total of 6.














Now say that these five guests were in fact pirates!!!! The plot thickens... So we want to find the percentage of Chuck Norris compared to the entire group of people. This is the part where you divide. Take Chuck Norris (1) and divide him by the total amount of people (6) which will get you .16 then to get the percentage, multiply it by 100 to move it over two decimal places. Then place the percent sign (%) infront of the number. Well done! You have just done a percentage equation!!










There is another type of equation, also needing another formula. This is used for things like sales on items. You're out to get this brand new pair of Adolf Dasler (Adidas' full name) shoes costing $79.99 and at the store the little price tag said 40% off on it. Now you're just thinking: "What?!??! I don't know that!" Ah, contrare, after you're through reading this, you will know! The formula for things like this is simple, think of it as: percent x whole = part. So in this case it would be 0.40 x 79.99 = 31.99. So you will get $31.99 off $79.99 making it $48.00. So hopefully now you will be able to do percents. Until next time, Robonorris out.

Chicken Problem

OK, gang. I NEED YOU TO START POSTING, so here's a small challenge for you. In the diagram are 3 chickens, each with a different mass. Can you tell me how much each one weighs? Describe your process - how did you come up with the answer?

To post a comment, just click on the "comments" hyperlink at the bottom of the post. You will be required to put your user name and password in (the one you used to set your account up when we did it together.)

Scales and Measuring Bears

What are scales? In a mathematical term, scales measure (typically) length and width. They are, simply, a representation of a full scale model/object based on a ratio and a proportion. A scale model can be one-half, one third, one tenth or even a thousandth the size of the actual. A scale model can also be larger that the actual object, two times, three times and even five times. Determining which number represents what model is the first step to solving a scale-type mathematical question.

Now here we have a little dilemma, let’s say, your friend has a strange desire to find out how much one centimeter of her teddy bear would stand up to a real wild grizzly bear. Now if the stuffed animal was around 40cm tall, and a real bear (if you got close enough to count) is about 182 cm tall; a scale would easily show you how many centimeters long are equivalent to your huggable toy. To find the answer, take the first two numbers (40cm and 182cm) and turn it into a fraction with 40cm as the numerator and 182cm as the denominator. Now with that fraction, make a proportion with the second fraction as 1cm as the numerator over x as the denominator (when you make a scale, the first number has to equal 1). Then cross-multiply 1cm by 182cm and divide by 40cm. Therefore, x equals 4.55; the ratio now becomes 1:4.55. Make sure you tell your friend that ‘for every 1cm of her stuffed animal, a real bear would be 4.55 cm’.

Once you measure an objects size, you can upsize or downsize by an appropriate number to compare the scale model to the full size.

You do this by taking the number of mm/cm/m (or any other means of measuring) of the full scale model or the actual item and turn it into a fraction. Then with that fraction, turn the equation into a proportion and with that proportion, comes the result of a ratio. So, to sum up; a scale is a ratio showing the differences between a length in a drawing/model and an actual length.

What is a Ratio?

Today in Math we learned about ratios. A ratio is a set of numbers that compare something to something else (see figure1). It can compare anything, fruits to Veggies, lemons to limes, or adults to kids.



There are 4 different ways to write a ratio. You can write it
- as is in figure 1, with a colon,
- as a fraction,
- as you would say it, or
- as a decimal (see figure 2).



Last, in order to do a math question with ratios, it must be done a certain way. i.e. if you were to do a question that asked “Find the unit price if 3 tickets cost $5.00. Do this using ratios.” you would have to set it up in a certain way. First, you write down what Professor Einstein has written in green (seen in figure 3). This is the base of the question. In both fractions, you must have the money amount on the top, and the amount of tickets on the bottom. Because we don’t know the amount of money that one ticket costs, we will put an “X” for that value. Next, in blue, we have to cross multiply. $5.00 x 1= 5.00, that is going to equal the other cross product which is 3X (seen in blue). In brown, we now see that he has divided both numbers by 3 in order to get the 3 on the right hand side out of the way (if you had something like 2X, 6X, or any other number and then X, you would divide by that number).


As you can see, Prof. Einstein has done the math for 5.00 ÷3 and has come out with 1.6 repeating=X. Except we have to make that $1.67=X because you can’t have a repeating decimal when dealing with money. Silly Einstein!

Time for Scribes!

To complete a scribe post the student must write a brief summary of what we learned in class today. Include enough detail so that someone who was away sick, or missed class for any other reason, can catch up on what they missed. Over the course of the year, the scribe posts will grow into the textbook for the course; written by students for students - remember that as each of you write your scribe posts. Ask yourself: "Is this good enough for our textbook? Would a graphic or other example(s) help illustrate what we learned?"
(graphic and text used by permission from: Mr. Harbeck)