How to Do Math In Your Head : Quick Math Tricks: Finding Percents in Your Head


Uploaded by expertvillage on 22.02.2008

Transcript:
Hi! I'm Sean with Expert Village and I'm going to show you tips and tricks for doing math
in your head. Finding a percentage of a number can be a little bit tricky, but it helps when
you think about it in the right terms. Let's take the number 329 for our example. If we
wanted to find 5% of 329, there's an easy method we can use. First, move the decimal
point over one place. 329 becomes 32.9. Divide that number by 2 and you'll get 16.45. That's
our answer. Pretty simple. Let's try a larger percentage. If we wanted to find 15% of 329,
we can start by just finding 10%. We know 10% is 32.9. It's just a simple movement of
the decimal. Now, we already know 5% will be 16.45. Add these together and you get 49.35,
which is our answer. Let's try 40% of 329 next. There's an easy way to get this one.
Multiply 329 by 4. You'll come up with 1316. Slide the decimal place and you get 131.6,
which is our answer. Percentages aren't really that different from any other equation in
your head. You want to look for the 10s. Finding the 10s makes it easy to slide decimal places
over and make the problems a lot less of headache. Whenever you're doing math in your head, the
most important part is being able to visualize the numbers. The more you practice, the better
you're going to get.