About this video
The video finds a green point on a number line from 1.5 to 1.7. The big blue marks are tenths, and each tenth is split into ten small spaces worth 1/100. Counting 7 hundredths past 1.5 gives 1.57.
You'll be able to
- tell what the big and small tick marks on a number line are worth.
- explain why 1/10 of 1/10 is 1/100.
- add tenths and hundredths to name a point, like 1 5/10 + 7/100 = 1.57.
Key words
- tenth
- One of ten equal parts of a whole, written 1/10 or 0.1.
- hundredth
- One of a hundred equal parts of a whole, written 1/100 or 0.01.
- hundredths place
- The second place after the decimal point; it tells how many hundredths.
- tick mark
- A small line on a number line that marks a number.
Transcript
- [Voiceover] Where is the point on the number line? Here we have a number line that starts at 1.5 or 1 5/10 and goes to 1 7/10. The distance between these larger blue tick marks is 1/10 because we go from 1 5/10 to 1 6/10, so that went up at 1/10 and then up to 1 7/10.
This distance here is 1/10 or we could write that as 0.1 or as a fraction 1/10. That distance between each of these blue large tick marks is 1/10, but we want to know what is this green point right here. To figure that out we also need to figure out what do these black tick marks represent, these smaller distances.
From here to here is 1/10, and within that 1/10th there are one, two, three, four, five, six, seven, eight, nine, 10 equal spaces. Each of these little spaces is 1/10 of this distance because it's one of the 10 equal spaces. This, right here, is 1/10th of this 1/10th because the large distance is 1/10th and this is 1/10 of that 1/10th.
Another way we could say that is 1/100. 1/10th of 1/10th, if you take 1/10 and divide it into 10 pieces, now you have 1/100. This distance is 1/100 which means that each of these distances, this is another 1/100 and another 1/100, so how many 1/100 till we get to our point?
Let's see. 1/100, two, three, four, five, six, seven, 7/100 is what it took us to get there, so we could say 7/100, the fraction or the decimal, 0.07 with a seven in the hundreds place. Looking at the whole number line now, putting the whole thing together, we started at 1.5 or 1 5/10, and we went another 7/100, so we can write that as +7/100.
We have 1 5/10 plus 7/100 which is a total of 1 57/100 or 1.57. Our point, right here, is at 1.57. 1 5/10 plus 7/100 gets us to 1 57/100.
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