### Video instructions and help with filling out and completing Which Form 8815 Index

**Instructions and Help about Which Form 8815 Index**

Standard index form is a way of writing either huge numbers or very small numbers into a format that we can apply more easily to our maths if we consider an example of the Earth's distance relative to the Sun how far is it between Sun yes well it is approximately 150 million kilometers now to use this number day-in and day-out could come with its problems in that I could miss count how many zeros I have and therefore my calculations are wrong before I show you how to write that in standard form it's worth considering the basics 100 can be written as 10 times 10 alternatively as an easier method we could write it as 10 squared now as a rule what I always say is the indicee matches the number of zeros that you need now is this principle that I want you to bear in mind for later on so going back to my original problem how do I write 150 million in standard index form how do I write it in a form which is the same as this but I could more readily use I could write 150 multiplied by 1 million but that in itself hasn't solved anything I still have a number of zeros which I need to record and I could lose track of alternatively I could write 1 million as 10 to the 6 the 6 being indicated by the number of zeros here now there's nothing wrong with that and indeed that number does match that I've not changed how much I've got but this doesn't appear the rules of standard index form which says that this number here has to be between 1 and 10 taking a step back I could write 15 times 10 to the 7 so I've increased the indices by 1 and reduce this by a factor of 10 so again I'm getting closer now that and that are the same number this is clauses 2 standard index 4 but this 15 is clearly not between 1 and 10 so my final step would simply be make it one point five times ten to the 8th so let's apply this to an example let's take 500 and seventy that in itself quite a small number but all I was to try and understand standing the next one a little bit better I need to write this as a number between one and ten so the first thing I would do is do five point seven eight now I can't change how much I've got so I have to get this back to that in order to do this I can multiply it by a hundred but standard index form using indices so how can I use that as an indicee well it would simply be five point seven theta multiplied by ten squared and it's as simple as that let's now apply that theory to a much larger number let's take four hundred and seventy eight million written in standard index form let me show you a little bit of a cheap way of doing this same principle applies the number has to be between one and ten I would start with four point seven eight then watch multiply it by ten now if the indicee which is the important part my decimal point in my original number is here now I've placed it here and that's a jump of one two three four five six seven eight is in the seat is therefore eight you must remember the decimal point never moves it is the numbers which jump over it but it's easy to do it one two three four five six seven eight places I hope that helps typing in standard index form numbers on scientific calculators is really really easy on both of these calculators working the same way if I consider my original example of one point five times ten to the eighth I simply type in the one point five I then need to find the exp button on both of these e XP means exponential and that is your x 10 book calculator is then waiting for the indices so then you need to just simply type in the eight and your number is then entered in it's important to remember on this calculator it doesn't actually show you the x ten on the display so don't go typing it is there in its memory knows that that's in there already on this calculate a little bit easier it does actually show you it on the display.