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# Visually converting tenths and hundredths

Sal rewrites 8/10 with a denominator of 100.

## Want to join the conversation?

- I asked for converting decimals tenths to hundreths but this popped up and I am not saying this is wrong but can you make a video about converting decimals tenths to hundreths(5 votes)
- how does he write so perfectly is he using a mouse because i sure cant write that perfectly with a mouse so what is he using?(4 votes)
- He might be using a computer pen(2 votes)

- how do you compater(2 votes)
- by making the denominators the same then multiplying the numerator by the denominator(2 votes)

- can you just do 8x10=80 and 10x10=100 and there you still and the same answer(1 vote)
- At0:28why did he say "Two Diagrams" they are not diagrmas?(0 votes)
- At0:38did he actually mean /200 or "in to /100? I got a little confused(0 votes)
- what if you have 12/100 and 20/10(0 votes)
- For 12/100, you would just need to change it to a thousand, so it would be 120/1,000 and for 20/10, make it into 200/1,000. Same thing like the last one a bit. Hope I answered your question.(0 votes)

- how can you convert tenths to hundreds?(0 votes)
- How would you go from '8/100' to '8/10' ? like could you use a decimal or fraction in the numerator to represent that smaller number?(0 votes)
- You multiply the 8/10 by 1/10 or 0.1 to reach the equivalent value(0 votes)

- How do you get the answer without a model?(0 votes)

## Video transcript

- [Voiceover] What I hope
to do in this fraction is be able to rewrite the fraction 8/10 as being something over 100. So I could put a question mark here. I could put a star over here. Star over 100. And what I care about is figure out what is this star equal to. Eight over 10 is equal to what over 100? And I encourage you to pause
the video to think about it. Now to help us work through this I have set up a little diagram,
or actually two diagrams to think about what 8/10 looks like. And then I have the same whole, instead of being split into /10, I have it split up in /200. I have it spit up to 100 equal sections. And we just have to figure out how many of these 100 equal sections are equivalent to the eight
out of the 10 equal sections right over here. So lets think about that a little bit. So once again, we have
10 equal sections here. And we have colored in
one, let me mark'em all. If we've colored in one, two, three, four, five, six, seven, eight of them. This diagram, this
picture, represents 8/10. 10 equal sections I have
colored in eight of them. Now how do I do that if
I'm talking about /100. Well it's the same whole right over here. Now if I want to fill up the
same amount of that whole, so let me get a little paint brush here. So it would the the equivalent of 1/10 would be filling in 10/100. So that's 10/100 right over there. Then 2/10 or that second /10, every time I fill in a
/10, that's the same thing as filling in 10/100. Let me write that down,
cause that's interesting. So we see here that 1/10 is equal to 10 over 100. Every time I fill in a /10, that's 1/10 right over there. If you look at this diagram, that's the equivalent to 10/100. It's equivalent to 10 of
those 100 equal sections. So if I wanna fill out 8/10, that's gonna be eight
time 10/100 or 80/100. And lets just see that right over here. So we already did 10/100, 20/100. This is gonna be 30/100. 40/100. 50/100. 60/100. 70/100. And 80/100. Notice I've filled in the same amount, and I can fill it in just to
make it a little bit clearer. But I filled in the same amount of both of these equal wholes. But over here, how many of
these squares have I filled in? I have filled in 80, now
let me get my pen going. I have over here, I have filled in 80 out of my 100 squares. While over here, I filled in eight out of my 10 equal rectangles. But they're the same amount of area. They're the same fraction of the whole. So eight over 10 is going
to be the same thing as 80 over 100. You see
it's the exact same thing. We've just divided the
one on the right here into 10 times as many sections. And you can even see it mathematically. Then look, if we divided into
10 times as many sections. So, if we multiply a denominator by 10 to go from 10 to 100. Well that means that each of
this eight sections in this one are going to represent 10
times as many in this one. So we would say, well,
eight is going to represent 10 times as many of the /100. So eight times 10 is 80. 10 times 10 is 100. 8/10 is the same thing as 80/100. And in general, if you're
trying to rewrite a fraction and not change its value, so you want an equivalent fraction, as long as you multiply the denominator, as long as you multiply the numerator and the denominator by the same thing, you will not be changing
the value of the fraction. It's also true if you divide the numerator and the denominator by the same thing. You also will not be changing
the value of the fraction. In this case we have
multiply both the numerator and the denominator by 10. And you see why we did it.