## Monday, July 25, 2011

### 1510 Week 6

What is a rational number?

I look at the above question and I think, "It's a..um...it's a number that is.....you know....rational. That makes sense." The definition according to the book "Mathematics for Elementary School Teachers" is "the quotient of a pair of integers (a/b, b is not equal to 0) that can be represented by a fraction or a decimal."

Like most math definitions, I think it sounds a bit more complicated than it really is. So I took to Google. What is a rational number? One site stated that it is any number that can be written as a simple fraction. Well that makes sense. I found this video on youtube that really helps clarify this.

Another real life math example...I love it!

So I do find this area of math pretty easy to understand. Understanding the meaning behind the math really helps solidify it is my mind. I guess that is the "Why?" Ok, so moving on to adding or subtracting rational numbers, like a decimal. It seems so "elementary" but I sometimes forget the basics behind the "easy" math because of the convenience of calculators. My current job is a banker. I work with numbers all day long. I NEVER use a piece of paper and pencil to figure out a deposit or interest, or a payment etc. I use the computer or a calculator. Can I do it without, sure. But, I don't want to make a mistake or take too long. Let's test my skills. Honest, no calculator.

56.45
+82.67
139.12

YES! I can do it. I know where to carry the decimal because there are only 2 places. Now let's try a little harder one and see how I do.

45.88769
+    23.882
69.76969

Got it! Whew. I will be honest, I was a little nervous because the decimals are not the same and I promised to use only my mad skills. All I did was added 2 zeros to the end to get my answer.

45.88769
+23.88200

I have to say, throughout this experience of recording my thoughts and what I have learned during his math course, I still get a smile when I get the answer right. Even if it is "easy". Come on, let's celebrate the right answer!

Another area I feel like I feel I should celebrate my understanding is adding and subtracting fractions and mixed fractions. Another "Duh." section, you say? . But, come on! How many really remember how to do it. I will tell you, I took my Praxis test (pretest for elementary teachers) and failed the math portion. Yup. I told myself no kidding you failed! When was the last time I added fractions?! Or did simple geometry on my own?! Too long. Well, I am retaking it now! You see what I have learned.....

3/4 + 2/3 = 17/12 or 1 5/12

(Little smile). I will leave you with this song by Tom Lehrer.