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## Arithmetic

### Unit 18: Lesson 3

Negative decimals and and fractions on the number line# Decimals & fractions on the number line

We're mixing it up by placing both fractions and decimals on the same number line. Great practice because you need to move effortlessly between the two. Created by Sal Khan and Monterey Institute for Technology and Education.

## Want to join the conversation?

- what is a number line?(26 votes)
- A number line is an orderly line of numbers. It helps with understanding the distance between the numbers.(13 votes)

- Can someone please explain the - numbers on the line? I always get that part wrong on the exersise! :P

Please feel free to coment.(38 votes)- «A negative number is any real number that is less than zero. Such numbers are often used to represent the amount of a loss or absence. For example, a debt that is owed may be thought of as a negative asset, or a decrease in some quantity may be thought of as a negative increase. Negative numbers are also used to describe values on a scale that goes below zero, such as the Celsius and Fahrenheit scales for temperature.

Negative numbers are usually written with a minus sign in front. For example, −3 represents a negative quantity with a magnitude of three, and is pronounced “minus three”. Conversely, a number that is greater than zero is called positive; zero is usually thought of as neither positive nor negative. The positivity of a number may be emphasized by placing a plus sign before it, e.g. +3. In general, the negativity or positivity of a number is referred to as its sign.»

From http://en.wikipedia.org/wiki/Negative_number(16 votes)

- could infinity be the number line or be ablo to plot(13 votes)
- Let's assume ,

We have plotted infinity in a number line.

Wait a second , do we know what is infinity ?

No we don't . So we can't plot it .

Let's assume,

We have accidently plotted infinity . But I can

say there is more on the number line . I can

plot infinity + 1 , infinity + 2 . So what is infinity .

I don't know .(12 votes)

- So is negative numbers like decimals?(10 votes)
- In a sense, negative numbers could be related to decimals because place values of decimal digits involve taking 10 to negative powers.

However, negative numbers do not have to be decimals (for example, -3) and decimals do not have to be negative numbers (for example, 0.2). While negative numbers are below zero, decimals have a fractional part (that is, the part after the decimal point).(4 votes)

- How does he make all these videos?(6 votes)
- Could I put a rational number in a number line?(5 votes)
- But what about something like 9/20 how do you put it on the number line?(5 votes)
- That's easy....you divide the space between 0 and 1 in 200 equal parts and then mark the 9th part. That represents 9/20.(4 votes)

- How Long Can A Number Line Be?(4 votes)
- Since numbers go on for infinity, a number line is also infinite, we usually fit it into our notebooks and textbooks by labeling down the numbers we are going to use, and then making an arrow at both of the ends in a number line to indicate that the numbers go on for infinity(3 votes)

- how would you graph this equation on a number line

f(x)=3x-2(1 vote)- That is a 2 dimensional linear equation, you need to graph that on a coordinate axis. F(x)=y=3x-2

A number line is one dimensional.(11 votes)

- Why is a number line called a number line? Why is a number line always horizontal not vertical?(3 votes)
- a number line can also be vertical. it is called a number line because it shows numbers, well, in a line.(2 votes)

## Video transcript

- [Voiceover] Plot the following
numbers on the number line. The first number we have here is five, and so five is five to the right of zero, five is right over there. That's our five. Then we get 1/3. 1/3. So 1/3 is between zero and one. We can actually split this into thirds. So that would be 1/3, 2/3,
and then 3/3, which is one, so 1/3 is going to sit right over there. It's 1/3 of the way from
zero to one, that's 1/3. Let me write that. That's
1/3 right over there. Then we have negative 1.2. I'll
do that in this blue color. Negative 1.2. So, negative
one is right over here. This is more negative than negative one. It's negative 1.2. It's negative
one, and then another .2, so it's going to be right over here. This is negative 1.2. Zero is pretty straight forward.
Zero is right over there. It's even labeled for us at zero. Five was labeled for us too at five. Then we have negative two and 1/4. So let's go to negative two. Negative two is here, and it's going to be more negative than negative two. It's negative two and then
another another negative 1/4. So it's negative two, and then we go 1/4 of the way to negative three. So negative 2 and 1/4 is
going to be right over here. So negative two and 1/4. And then finally we have 4.1. 4.1. So four is right over here. .1 is another tenth greater than four, another tenth on the way to five. So four and 1/10 is going
to be right over here. 4.1. 4.1. And we are done.