 Ok, so this next problem is kind of interesting because it gives you some sort of ability to judge scale and also hopefully afterwards you can see how cumbersome or silly it is to write all those zeros and just start using scientific notation you are going to want to. So just like we taught you in class, so you are just going to want to move the decimal place, the decimal point to the behind the first non-zero digit. So in part A, so that's the length of a hydrogen chemical bond. It's hard to read that number with all those zeros. So if we move it 11 spaces to the right and put the decimal after the 7 and then the 461 after the decimal and then you multiply that by 10 to, in this case it's going to be negative because you moved it to the right, 11 and you moved it 11 times so that's where you get that number from and then remember your meters, your units. Ok, so you are going to use that same sort of strategy, problem solving strategy with the rest of them. So you see here the next one it's the number of miles in an inch, well that's going to be a very small number so move the decimal point 5 places, you see that. The next one is the wavelength of a red light, so wavelengths are very small. These are all denoting very small numbers, they are all less than one of their respective units so that means they are pretty small. So 6.32 times 10 to the negative 7th and for D you are moving the last one 5 spaces to the right so 1.5 times 10 to the negative 9th meters, ok so don't forget your units and if you have any questions let me know.