Life without a calculator

Lets imagine life, for one second, without calculators. Scary, isn't it?! What would we do without them? We would ESTIMATE! It is very important for people of all ages to learn all about estimating and why its so important. First, I am going to share some important information with you that I learned this week in my college math class.

There are three main types of estimation:

1. Estimating the Quantity - finding how many students, days, lunches, classes, etc.
2. Estimating the Measure - finding how much length, area, volume, time, etc.
3. Estimating an Answer - finding a sum, difference, product, or quotient.

There are also many different techniques for estimating. I am going to share a few of my favorites with you. But, keep in mind...what works for some, doesn't always work for others! So experiment and see what works best for you! 

Rounding is based on locating the point halfway between consecutive multiples of 10, 100, 1000 and so on. So how would be round 208? You got it, 200!

Front end estimation is calculating the leftmost or "front end" digit of each number as if the remaining digits were all zeros. How would we front end estimate 258+365+102....200+300+100.

Clustering involves looking for the number about which the addends cluster and then multiplying by the number of addends. Take the numbers 48 55 47 52 and 53 for instance, we would cluster them around the number 50 and since there are 5 numbers that cluster around 50 you take 50 x 5 for your answer.

Now, your probably wondering why I am wasting your time telling you about these techniques. Well, I'm not. Now its time for a little story:

I was grocery shopping the other day with $100 (I give myself a budget because otherwise I go a little food crazy). While I was shopping I had to make sure I didn't go over my budget. So, while shopping I was using the rounding technique to make sure that I wasn't spending more then my limit. When I got the check-out, I still had $7 left over for extra money, but at least I didn't have to send something back because I was $7 over....we all know how embarrassing that is. This was made possible because I estimated how much each item cost. Brilliant, huh?!

Next time you think that estimating is a waste of time because we have calculators, remember...we don't always have calculators with us and we will need to know how to estimate our problems out.

Some more information on estimating is available at this website:
http://www.aaamath.com/est.htm

Still a little confused? Here is a great video with some examples on estimating and some more reasons on why estimating is so important! Enjoy!