web2.0calc
 

All Answers 358512 Answers

  Questions   
Sort: 
 #2
avatar+118725 
0
desiree123:

three plus negative two



***If you want to understand negative and positive numbers better read through here.

Positive and negative numbers

For multiply and divide it is very simple. If the signs are the same then the answer is positive. If the signs are different the answer is negative. See, simple.

For addition and subtraction it is a bit trickier.
I am a big user of number lines. Until you get used to it you should actually draw your number lines. I am assuming that you know how to do that.
Zero in the middle, positive numbers going off to the right, negative numbers going off to the left.

Say it is 1+6. You start at 1 then go 6 places in the positive direction and you get 7 (yea, I know, you already knew that)
Now -3+8 Start at -3 and go 8 in the positive direction and what do you get?
Now 4 - 9 start at 4 and go 9 in the negative direction and what do you get?
Now -2- 8 start at -2 and go 8 in the negative direction and what do you get?

When you get good at it you can stop drawing the number line but you should still imagine it. If you use a note book, imagine 0 in the crease of the book, the positive numbers will be on the right and the negative numbers on the left.

Now, what about those pesky + - things
for starters, If you see something like 7+(-8) it is exactly the same as 7+ - 8 (You can put the bracket in or take it away - it doesn't matter.)
That goes for 3 - - 6 = 3- (-6) as well.

Now think of a thermometer. 0 degrees is in the middle. The positive numbers are hot numbers. The negative or minus numbers are cold numbers.
Let's think about 4+ + 5 you are adding heat so it must get hotter. So it is 4+5
What about 6+-7 This time you are adding cold. So it has to get colder. It must be 6-7
And 8 - + 3. This time you are taking away heat so it has got to get colder. It must be 8-3
and lastly -1 - - 4. This time you are taking away coldness so it has to get warmer. It must be -1+4

With pluses and minuses you can also think of it like this.
If two signs are so close together that you can put a circle around them without anything getting in the way then,
if the signs are the same you replace them with a positive.
if the signs are different you replace them with a negative.

am going to give you some questions to answer now.

1) Now -3+8 Start at -3 and go 8 in the positive direction and what do you get?
2) Now 4 - 9 start at 4 and go 9 in the negative direction and what do you get?
3) Now -2- 8 start at -2 and go 8 in the negative direction and what do you get?
4) 0-8=
5) -2-+6=
6) 1-4+(-7)=
7) -9++4 =
8) 13+(-5)=
9) -4 x 6 =
10) 3 x -6 =
11) -5 x -3=
12) 20 / -4=
13) -8 / 2=
14) -15 / -5=
15) +4 x +7=
answers are in this page
http://web2.0calc.com/questions/viewtopic.php?f=2&t=8788&p=18737&hilit=negative+numbers#p18737
Feb 21, 2014
 #3
avatar+6252 
0
are you for real?
Feb 21, 2014
 #2
avatar
0
My 14-year-old, eighth-grade nephew just called me about this post. I’ve not heard him so excited about math since I showed him how to find the height of a tree using a pan of water and basic trigonometry. He now knows what Aleph numbers are and that Georg Cantor discovered them. He’s now reading about least squares and wants me to help him learn how to do them. I will have to brush up myself to do this.

He doesn’t ask a lot of question here (he has an uncle who helps him), but he reads this forum every day. I know he, and his parents, are grateful to the teachers (especially Melody, and lately, ROM) and other students who help him learn. One student by the user name of Puzzled went beyond the norm of this site and answered one of Melody’s puzzle questions, using a divisor solution presented by another member. My nephew learned how to do this too. An eighth-grader is learning High school or college level math, who, just a few years ago, had to be bullied and bribed to learn his multiplication tables.

Mr. Dodgson’s post alludes to mathematics that are in the Einstein and Hawking classes of theoretical physics. He probably posted it because he was excited to find a value that generated a result in his programs. I am distantly acquainted with one or two persons who might approach this level of skill. They live in their own world. To them, grade-school children or engineers are not significantly different in intellect. Most would understand that $1000 is much more than a $1, but if you are a billionaire, it is insignificant.

In spite your sarcastic comment, Mr. Rom, my nephew “found it most illuminating!” It piqued his interest in advanced mathematics. I’d be pleased, if it was a science fiction show full of malarkey, if it directed him to the real thing. Coming from a post on a web forum with skilled teachers and tutors, and the occasional visiting “Einstein-classed” mathematician, is much better.

Mr. Dodgson may also have posted to deliver a “tip of the hat” thank you and acknowledgement to you, Mr. Rom. He does say, “Thank you” and “You have a great forum, here. …” Obviously, he spent time reading the posts while his computer was “cooking his stew.” A reasonable assumption is to think he would recognize the forum as primarily for young persons. (On the other hand, he may be an idiot savant).

Though he lives in his own world most of the time, he apparently visits this one occasionally. Long enough to consider that $1000 is in fact more than a $1, and you (and a few others) might have an inkling of his concepts. After reading your posts, he may have thought you worth a $1001, before returning to his wonderland world where it doesn’t really matter.

Just a non-mathematical thought from the cyber world, where you never know who you will meet.

BTW, do you have an opinion on Mr. Dodgson’s post, other than your current one? If so, my nephew would be very interested, and I would too.

Sincerely,
George MacDonald
Feb 21, 2014
 #3
avatar+5478 
0
Rom beat me to it
Feb 21, 2014
 #7
avatar+118725 
0
That is EXCELLENT!
Feb 21, 2014
Feb 20, 2014
 #1
avatar+6252 
0
not that I can see
Feb 20, 2014

0 Online Users

Top Users

avatar+130561 CPhill moderator
avatar+37193 ElectricPavlov
avatar+15147 asinus moderator
avatar+2447 Bosco
avatar+1837 blackpanther
avatar+1761 parmen
avatar+1572 kittykat
avatar+1317 AnswerscorrectIy
avatar+1011 gnistory
avatar+987 booboo44
avatar+869 cooIcooIcooI17

Sticky Topics