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Comparing numbers of objects
Sal talks about what "more than" and "less than" mean. Created by Sal Khan.
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- how do we know that which number is more than, less than, same as? is it the same with the fractions?(0 votes)
- If you have one natural number (1) and want to know if other number (5) is less/more/same by counting, you can count from zero to the number you want to compare (5). If you come across that one number (1) and continue, then the number you are counting (5) is more than the original one (1). If you don't (for example you go up to three and want to compare it to five, but you go just 1,2,3 - three is less than five) then the number is lower. If you stop at the same number you are comparing to, then the numbers are equal.
Probably best way to view it is that you have the numbers arranged on an axis that has zero "in the middle". Then if you go to right, you start counting 1,2,3 and so on. Every number you come to is more than any of the numbers you have already came across. If you instead go to the left (from zero you would go into negative numbers, but you can turn left anywhere) for example from number 10, you go to 9,8,7,6... Now 8 is less than 9, 7 is less than eight which means it is also less than 9 and so on. If you stop on some number and look at it, that is the number that has the same value as itself (and the only one on the axis of integers).
With negative numbers you would go left from zero to -1, -2, -3,- 4... So as you can see -4 is less than -1, although 4 is more than 1!
With fractions it is a little more difficult. If they have the same denominator (number below line), then you can just compare numerators above the line the same way as with integers.
If they don't have same denominators the best way would be to convert them so that they have. This would involve multiplication. There are more denominators you could convert two numbers to, but again the simplest would be just multiplicating these denominators. You need to multiply both numerators as well by the same denominator. So you would take denominator of the first fraction and multiply both parts of the second fraction by it. Then you would take the original denominator of the second fraction and again multiply both parts of first fraction by it. Then you have two fractions with same denominators and you can just compare the numerators again..(2 votes)
- What's the difference between more than and less than?(0 votes)
- More then means that 9 is larger, or bigger, number then 6. Less then means that 4 is smaller then 8.(3 votes)
- How do I learn how to count?(0 votes)
- Khan academy has a wide video range starting with counting.. Please visit these :-https://www.khanacademy.org/math/early-math/cc-early-math-counting-topic(1 vote)
- Instead of counting one by one, can we count by 2's,5's, and 10's so it would not take too long to count?(0 votes)
- If the number is small, like 10, you could count by 1s or 2s or 5s...if it's a big number, like 100, you'd want to use 10s or somehting like that. It really depends on the number.(0 votes)
- Is counting numbers is same thing as natural numbers?(0 votes)
- The set of natural numbers is maybe exactly the same as the counting numbers, since many people define the natural numbers as either the set of all positive integers (that is, {1, 2, 3, 4, 5...}) or the set of all non-negative integers (that is, {0, 1, 2, 3, 4...}).
More info: https://en.wikipedia.org/wiki/Natural_number(0 votes)
Video transcript
Voiceover:Gavin has these horses. Is the number of horses
in each picture below more than, less than, or same as the number of horses Gavin has? Let's first look at how
many horses Gavin has. He has one, two, three,
four, five, six horses. Let's remember that and let's compare each of
these amounts of horses to the six horses that Gavin has. Let's look over here, over here we have one, two, three, four, five, six horses. This is the same number that Gavin has, they're just arranged differently. This is the same, we'll put in the Same as bucket. Now, here we have one, two,
three, four five horses. This is less than the six
horses that Gavin has, five is less than six. Here and I can just look at this and see that there's more than six but we can count them. We have one, two, three, four, five, and then another five
that's going to be 10. Or we can say one, two, three, four, five, six, seven, eight, nine, 10. Well 10 is more than six, 10 is more than six, so we'll put it in the More than bucket. Now here we have four and four well that's going to be eight. One, two, three, four, five, six, seven, eight. It's again, that is more
than the six up here. That's more than six and then here we have one, two, three, four horses. Well four is less than six, so I will put that, I will put that in the less than, in the Less than bucket just like that. Let's check our answer to see how we did. We got it right.