Estimation and High School Students.

I've discovered that most of my students have trouble with estimation.  In fact, they often equate estimation with making guesses rather than using certain strategies to come up with a reasonable answer.  I'm not sure how much instruction they get in the earlier grades but I do know that estimation is an important skill to have.

First of all, estimation is a higher level skill requiring  students to understands the concepts and carry out mental math manipulation.  They have to look at the numbers in a problem, decide if they should round up or down while keeping a running total.  

Basically, it is important to help students develop the ability to estimate because it shows how well a student understands the concept and the reasoning behind it when they are not relying on the standard step by step procedures.  In addition, it helps students develop strategies which in turn strengthens their problem solving skills and logic and as stated before, it helps develop their number sense.  It is also a great skill to have when planning for things such as a Thanksgiving dinner.

Furthermore, the ability to estimate helps students develop number sense so they know if their answer is reasonable.  Without a developed number sense or ability to know if their answers are reasonable, it is much easier for students to make computational errors.  The other day, I discovered my highest level students in Math didn't seem to grasp that when they are due to get a raise every year, their salaries should be going up.  Over half the class had a decreasing amount earned.  This tells me they lack certain skills.

Second, estimation allows students to carry out mental math faster because they can round numbers to come up with ball park figures. This is an important skill in business where people look at the estimated costs for upcoming projects.  Someone who is good at estimation can look at the numbers, do some quick calculations in their head and come up with an estimated cost for the whole thing.  They rely on spread sheets to do the actual calculations.  

In addition, to estimating using addition, subtraction, multiplication, and division, students also need to be able to estimate how long it might take to do something, or how long it might take to travel from point A to point B or even how many calories in the cookie they are eating.  

It is worth taking time to discuss why estimations are important in real life and the type of estimations one runs into.  There are general estimations such as why the local football field might want to estimate the number of people who are planning to attend the next football game?  Aside from an approximation of the amount of take at the gate, the concession stands have to know so they have enough food or souvenirs available to sell.

Or if you need to have something fixed, most people get estimations before they agree to have the work done so they can plan for the output.  Although the estimation is usually a specific amount such as $3967.28 for redoing the plumbing in the bathroom, or $256.98 to have the breaks redone, we rely on that as being the largest amount we pay.  

Unfortunately, the math books I use at school do not really address estimation.  That is a shame because estimation is such an important skill.  I'm working on figuring out how to integrate it into my classes so students get better at it.  I'll talk more about it another time. Let me know what you think, I'd love to hear.  Have a great day.