Hello and welcome to the first video of the binary numbers. In this video. I would like to introduce you to the binary numbers and the binary number system, but for us to understand that we need to look at what the decimal number system is and we need to look at the powers because powers are at the heart of every number systems. So let's start with the powers. 3 to the power of two is 3 * 3. And for example, 5 to the power of four is 5 * 5 * 5 * 5. So there are two important concepts in here, the power. And the base, they both can be any different whole numbers. So the power tells us how many times we need to multiply the base together. So in this particular case, four tasmac 2 multiplied the base 5 by itself four times, and in the example of three, the two tags need to multiply the three by itself twice. Now there are two important powers that we need to draw your attention to the first one. Is any number to the zero power is by definition is always one. For example. 7 to the power of 0 is 1 two to the power of 0 is one and 10 to the power of 0 is also one another important power. Is any number raised to the first power is just the number itself for example? 7 to the first power equals to 7, two to the first power equals to two and 10 to the first power is equal to 10. By definition, the decimal number system. Is a base 10 positional. Number system. Which uses 10 digits. And these 10 digits are 012 all the way up to 9. So that's the 9 digits plus zero, which makes them 10. Now what does it mean based on and positional the base 10 taskview that using 10 digits and every place value or every position is represented by powers of 10 and it's a positional number system because if you place digits at different positions they represent different values. The former mathematics is representing each of the place values tend to zero 10 to the one. 1:50 2:50 and so on now what they mean as numbers? 10 to 0 as we said before, it's 110 to the one Eastern tented it too, is 100 and 2:50 is 1000. It might seems a little bit overcomplicated when you think about the decimal numbers, but it is already built into the way that we read our numbers. For example, if you read out 573 just the way you say the number you talk about decimal place values 573, so the hundred 500 tells you that five is at the hundreds place. The 70 tells you that 70s at the 10s place and three tells you that three is at the units place. Now, what happens if I use the same 3 digits but in a slightly different order? So what happens if I say 735? Well, as I was reading out the number. You probably notice that now is 7 at the hundreds place, three is at the 10 space and five is at the units place. So depending on which place value and placing or which position and placing the digits, they will represent different values. The five in the first number is 105 in the second number is just five units. The three in the first number is 3 units, but in the second number. E 310 switches 30 and the seven in the first number is seven 10s, which is 70 and in the second number is 700 which is 700. Now I would like to draw your attention to the rule of the zeros because so far I just picked out any digits which is a non 0 digit. But what happens if I have good zeros in my number? For example? What's the difference between 1007? Andseventeen well without having the zeros in the number I end up with a very much smaller number, so the zeros are so-called place value holders. So today telling me that at this place value I'm not using any of the place value by placing the zero. So in this case I'm using seven of the units, not using any of the 10s an I'm not using any of the hundreds and I'm using one of the thousands without the zeros here. I'm just telling you that I'm using seven or the ones and I'm using one of the tents. You will agree with me that the two numbers are very, very different, so every time I need to build up a bigger number without using the in between place values, I always had to place a 0 here. Now we can build up a decimal place value table and the former place value table would look like this. It's just basically the heading you have got the powers and the equivalent decimal values. Now how can you use a place value table like this to position different numbers in that? Now we talked about a few different numbers, so let's see what they look like in the place where you table so. 573 you put a five in the hundreds, seven in the Times Seven in the 10s, and three in the units column. If we talking about 735, we mix up the order. Of the digits 17. One of the 10s. Seven of the units and 1007 one of the thousand. None of the hundreds. None of the 10s and seven over the units. One thing I'd like you to notice is when you look at the place value table. If you're going from right to left, you can spot that the numbers from place value to place while you get 10 times bigger, so the values themselves, the place where used gets 10 times bigger. Now if we reverse the order and we going from left to right, the place values themselves get 10 times smaller, so this is again another important feature of the place values themselves, which will help us to extend the place value table in a later video to introduce smaller numbers. Now we have got all the conceptual understanding that we need to build up the binary numbers. Binary numbers are very important for computer science because binary numbers are basically the way to communicate to the computer. Remember that the computer at a very basic level will type up small electrical circuits, and you can either turn on electrical circuits on or off, and in the different combinations of these electric circuits you can tell the computer to do different instructions. So depending on what kind of binary number instructions you're giving to the computer, the computer will carry out different calculations or different instructions. By definition, the binary number system is base two positional number system. We using 2 digits. And these two digits are zero and one. So what does the place where you table look for the binary numbers? But because it's a base two number system, every place value is a power of two. So what are these powers? 2 to the power of 0 two to the power of 1 two to the power of 2 to the power of. 3 two to the power of four. 2 to the power of 5 and I can go on forever. As you see the differences now. That instead of base 10, I'm just replacing the Terminator 2, but the powers themselves stay the same. Now what does it mean for the actual values? What is 2 to the zero? While remember any number to the Zero power is 1 two to the one, any number to the first power itself, so it's 2 two to two 2 * 2 is 4, two to three 2 * 2 * 2 is 8, two to four is 16 and two to five. He's 32 and I can go on for higher values. So when we look at the place values themselves compared to the decimals, Now when I go from right to left, the place values get doubled. So from one we can get to 2 from 2 began get to 4 from 4 we can get to 8, they double up and if I go from left to right the opposite direction they get halved from 32 to 16 I get by having it and from 16 to 8 I get by having it again so. This is a common feature of the place where you tables any number system because there are other different number systems. Every time when you go from right to left, the place values get multiplied by the base. And when you go from left to right, the place values get divided by the base. So when we look at the binary place value table, it's like the numbers I showed you before, but put into a nicer format. So what happens in the here in the decimal place value table? We had quite a lot of different digits that we could play around with. We had the digits from zero to 9, but what happens in binary? Which 2 digits can we use here? Just the zero and one. So. A binary number is nothing else but a string of ones and zeros. For example, this is a binary number. What it means then for the place values is that with one I'm saying that use the corresponding place value and with zero I'm saying don't use the corresponding place value, so the placeholder property of the zero becomes really important and comes up a lot more often than in decimal numbers. Let's look at a few more binary numbers. So basically I can just use any ones and any zeros and place them in any order whatever to build upon binary number. So let's say 1011001 it's a binary number, 100001 is also binary number, or 1011. Again a binary number. Now you probably notice that because we only using ones and zeros. Every single one of them could also be a decimal number. For example, the last one could be 1011 in decimal. So how can we make a distinction between binary and decimal? So there is a very common notation to distinguish between binary and decimal numbers. So if you see a number which only uses ones and zeros to make sure that this is a binary number, you put a little two in subscript. And if you want to indicate that this is a decimal number, you put a little subscript of 10, indicating that this is a decimal number. So if it's not clear enough from context, always look for the subscript. It is a binary number. Or is it a decimal number? Now it's very, very important that you are making difference between the number itself and the notation of signaling which system working in this letter notation, the number 2 and here the number 10 are not part of the number. As long as the calculations go. This is just a way of telling me or you or anybody ask that this is a binary number. Once we are aware of that, this is a binary number. This two becomes redundant, so as long as the calculations go, you can leave this number. So I hope that you have a better understanding of the binary and the decimal number systems in the next few videos. I will show you what we can do with the binary numbers.