Author Archives: hangtime
Scientific Notation On Your Calculator (free)
You're all "I know how to do exponents on my calculator." Yet of all the students I've tutored over the years in physics and chemistry, exactly one knew what I'm about to tell you in this video. Yup, the EE button! This prevents the most common mistake students make on their calculators with scientific notation, which is getting screwed up when their calculator is better at PEMDAS than they are!
Converting Numbers to Scientific Notation
As the title above says, we'll go over a 3-step process to convert any number into scientific notation, which is really what you have to do most often in class. We'll also cover how to multiply numbers in scientific notation, and when you have to convert numbers that aren't in proper scientific notation form.
Converting Scientific Notation to Numbers
Most people get that the exponent on scientific notation tells you "the number of zeroes". But what does that really mean? In this video I'll show you how to convert a number that's already in scientific notation into a number that's not. There's a slow way and a fast way, so you'll have two ways to choose from. And with this solid foundation we'll be able to attack the next video.
This chapter covers the basics of scientific notation, both converting it to regular numbers and back again. Decimals, huge numbers, multiplying scientific notation numbers together, positive exponents, negative exponents, "base 10", etc. it's all covered.
Tough Rate Word Problems
The examples in this video are a little tougher. Two trains headed towards each other or trying to catch up. A kayaker paddling upstream. Rates other than speed. All is covered here. If this video isn't hard enough for you, you're probably in Algebra 2 or College Algebra, and you should check out these much harder videos.
Basic Rate Word Problems
The problems in this video are all "one step" problems because they just involve plugging into the rate-time equation once. Whether you're solving for time, rate or distance, if your problem only has one driver or train or whatever, this video is for you.
Rate, time and distance show up in these word problems (Rate x Time = Distance). Example problems include: How far did someone drive in 3 hours? If two trains leave stations and different times, how long until they pass each other? What units should my answer be, and how do I convert?
How to Add & Subtract Decimals
In classes that use a lot of decimals -- usually science -- you're almost always allowed to use a calculator, so you won't have to be able to do this by hand for long!
How to Divide Decimals
Long division of decimals is a lot like long division of whole numbers. The main difference is that sometimes you'll move a decimal around, or need to tack on some extra 0's to the end of the number, so this video will cover all that stuff!