Math About Me

Lesson Frame

• We will calculate the day of the week we were born AND how old we are in seconds.
• I will explain how the two math activities may have changed my mind about math.

Lesson

I will admit that I actually scared my 5th graders to death when I showed them Zeller's Congruence algorithm that allows you to calculate the day of the week you were born:

I did explain that while we would be using this algorithm, I would be breaking it down into smaller pieces for us to work with.  I just wanted them to be aware that there was an algebraic algorithm and to expose them to what it looked like.  It allowed me to use and explain terms such as variable, GEMDAS, and algebraic equation.

A nice explanation of how to calculate this is found at https://plus.maths.org/content/what-day-week-were-you-born .  This is something you will want to work through before presenting it to your students, but once you understand it, it is easy to explain.

Once we completed the math, we actually went online and tested our answer using Math is Fun.  The kids loved this.

Now they were hooked and eager to discover more math about themselves.  The next activity I chose to use allowed them to find the (approximate) number of seconds they have been alive.  It was approximate as we did not calculate from the moment of birth.  For upper grades you can have a more precise calculation, but for my purposes, we used general information and a calculator.

1. We wrote down how old we were.
2. We multiplied our age x 12 and added the number of months from our last birthday to today, to give us the number of months.
3. Next we moved to weeks, using the above answer, we multiplied by 4, as there are about 4 weeks per month.
4. Now it was time for days, since there are 7 days in a week, we multiplied the answer above by 7.
5. Hours:  multiply above answer by 24
6. Minutes:  multiply above answer by 60
7. Seconds:  multiply above answer by 60

I know that there are additional ways to do this and probably more accurate, but I just wanted my students to have fun with math the first day of school.  What they really enjoyed was comparing their answers to a website that gives a much more accurate answer, Math Cats.  My students loved comparing their answers, and while their estimates were much lower, they were within a reasonable range!

There were a couple of things I really liked about this site.

1. The seconds are changing constantly and every minute the minutes change, etc.
2. If you new the exact time you were born, you could add that information into the program and see EXACTLY how many seconds old you were!

Close

To close the lesson, I asked my students to explain how the two activities we completed may have changed their mind about math.

Two of my favorite responses:

I have to admit this changed my mind about math class.  We had a spectacular time and didn't realize we were learning.  Mrs. Dittrich, I have to say, you changed my mind about the class.

It changed my mind about math because it was so much fun, but we were still learning.  I will look forward to coming to math class even more.