What do two negatives make

You should buy it. Click the photo for a link to the amazon page, or this link for the ebook. Email Address. Skip to content. Home About Faq. If so, where? Q: Is there a real life example where two negatives make a positive? Posted on March 3, by The Physicist.

Email Print Facebook Reddit Twitter. This entry was posted in -- By the Physicist , Philosophical , Physics. Bookmark the permalink. The Uncertain One says:. January 18, at am. I can think of two examples. How can Alice know how many apples are in the basket, now that she has the correct information? I tried to explain this to the officer, but he insisted on giving me a ticket and a warning. Killian says:. July 20, at am. Think of a video displaying an object in motion. Say the object is going 5 mph.

Then if you fast-forward the video speed 2x, it will appear to be going 10 mph. Then if you rewind that, you get an object going forward at 5 mph. August 21, at pm. Stan says:. May 29, at pm. The Observer says:. September 6, at am.

Strategies of war says:. Press ESC to cancel. Skip to content Home Physics Why do 2 negatives equal a positive? Ben Davis February 10, Why do 2 negatives equal a positive? Does two negatives make a positive in grammar? How do you calculate negative numbers?

Do you distribute the negative? What does distribute the negative mean? Why do you distribute the negative sign? How do you distribute variables? What does a negative sign look like? What are plus and minus signs called?

We could have had a different order of operations or a different base or a different way of interpreting composition of functions, etc. But having the product of two negative numbers be positive has underlying logic that we can get at in various conceptual ways. Remember it! What a foolish and harmful misuse of mnemonics. Well said! Many people think they know what is a negative number,which actually is incorrect.

Before everyone had digital cameras, people used film, and there was a negative of the film. If one took a negative of the film negative, one would obtain something that looked like the original photo. I say we introduce negative numbers in the second grade. Then we can get rid of this subtraction nonsense, and reduce the number of basic operations that need to be taught.

During a lecture the Oxford linguistic philosopher J. Austin made the claim that although a double negative in English implies a positive meaning and in French a negative one, there is no language in which a double positive implies a negative.

Actually,Humans have adopted the convention,that whenever they encounter with a pair of elements,having opposite nature behaviour , it would be nice to name one of them as positive and the other as negative. Consider in Physics. Why have we named electronic charge as negative and protonic charge as positive?

We could have worked with Electricity by naming the electron charge as positive and the proton charge as negative! Nothing will change! Except the terminology. So,in Mathematics too, we find a natural number quantity and a negative integer quantity as opposite. Think that you just now have pennies. So you have ,with no complex confusion. You can have whatever you can by your owned pennies. Again,consider, a different situation.

In this situation,it is far away of thinking what to buy,instead you are to think how to pay him back pennies. So,here, we have a pair of opposites,both regarding pennies. So,if in the first case,you have pennies,then how much do you have in the second case? Yes,the opposite of what you had in the first situation. So what is the opposite of the number ? Also one more thing I would like to include here,that the sign minus — , is a symbol, that we PUT between 2 numbers. Then what does it mean by, for instance, -5?

From what is 5 subtracted from? Does that literally make sense? Obviously, if you have something nothing that is 0 , and still need to give someone 5 things of what you have,then obviously you are forced to do the operation 0 — 5! In short, without loss of generality, -5 is just a compact form for writing 0 — 5. John Allen Paulos makes the case in his classic book Innumeracy for using a debt model to understand not only addition with negatives but also multiplication with negatives, too.

Gauss says otherwise. Such heartwarming nostalgia. I actually want to go back to school now. Thank you for this post. We start out learning about numbers, whole numbers, by adding and subtracting them. We can picture and hold representations of them.

Then we learn to multiply these positive numbers. Multiplication is a short-hand way of adding numbers. So far so good. You could also picture this, as recommended above, to think of this as a matter of directions. I cannot find a way to express this as an addition question. Multiplication IS addition. Just as division IS subtraction. One teacher tried to explain it thus: two bad people leave town three times.

Lots of mathematicians throughout history quibbled with it or resisted it. A little late, but not fifty years late…thanks, Ben. My mind is slightly less boggled. That makes some sense, if we accept those rules.

My inner 15 year-old is still balking somewhat. That seems like magic. Positive three, I can hold that in my hand. Is there any other world, other than directions vectors? Maybe that would help. It definitely resonates for some people though and is good to have in the repertoire.