Age: 1 month

Age: 14 years

     The question "How old are you?" or "How old is he (or she)?" actually has more than one type of answer, depending on the individual concerned. For instance, you, the readers of this webpage, will probably reply with statements like "I'm 14 years old", or "I'll be 25 next month". (Scroll to the bottom of this article for a humorous treatment of this concept.)

     But if the parents of a newborn baby or a very young child are asked the same question, their answers are would probably be something like "He's just 5 days old.", or "She just turned 3 weeks old today.", or "Last week he was 10 months old". You see, we tend to use units of time that are appropriate for the situation.

     This brings up an interesting question, that I bet you never thought of before: "How old are you today IN DAYS?" In reality it is nothing more than a basic math problem to calculate. After all, it involves only a little simple arithmetic, perhaps a calculator, knowledge of a calendar, and genuine problem solving -- all with a personal touch.

     As a schoolteacher, I feel this activity is guaranteed to capture the interest of most students. When I present it (usually to students at the 4th-5th grade levels, with their teacher accompanying them), I begin by asking a child selected at random: "How old are you?" Usually the answer is: "I'm 9 (or 10, etc.) years old." To which I reply: "Oh, nice, today is your birthday." There follows a lot of giggles. "No, it's not!" I then say: "Well, you're not really 9 after all. You are 9 years and some days more, right?" Of course, they can agree to that. So we then dive into the main aspect of the activity: to determine one's age IN DAYS, instead of the usual years.

     I use an example to demonstrate, often my own son's age. [Those are photographs of him, his mother and myself at the top of this page, if you haven't figured that out. ;) ] Since he was born on Dec. 22, 1983, I usually do the activity around March or April. [The reason will soon be apparent.]

     Let's assume a presentation date of March 14, 1997. The following is written on the board and discussed/explained step-by-step. [The words inside the brackets are presented merely here for explanation, not written.]

Kevin Trotter: Dec. 22, 1983
1. 365 x 13 = 4745 [age at last birthday party (1996 - 1983) times the number of days in a basic year; this is where the calculator helps with younger students]
2. LYD(96, 92, 88, 84)      = 4 [LYD = leap year days; the years in which a Feb. 29 occurred; here counting backwards by 4s is fun, and instructive.]
3. Dec = 9
    Jan = 31
    Feb = 28
    Mar = 14
[no. of days left in the birth month, after the party, so to speak]
[no. of days lived in January]
[no. of days lived in February]
[no. of days lived SO FAR in March]

[no. of days lived SINCE his last birthday party]
4. 4745 + 4 + 82 = 4831 days

     Then we finish things off with a "summary statement": "Kevin is 4831 days old today."

Teaching Advice

     I often then repeat the procedure for the class's own teacher's age. That really perks up the kids' interest! Then they find their own ages, or mine as well. Later they are encouraged to do likewise for their parents and other family members. A wealth of practice is thus generated that is quite meaningful to any student.

     I've found that it's better to use, as an initial example, a date of birth (i.e. month/day) 4-5 months prior to the lesson date. It's so that in Step 3 there is a medium length list of post-birth-month entries -- not too long, not too short. In practice, if it's too long, it worries the kids (it's a LOOONG problem!); if it's too short, they get "the wrong idea" (they generalize that this is a quick list). However, they must learn to accept variations and surprises as they come up. Some Step 3 lists are long; some are short. "It all just depends."

     One of the most interesting aspects of this involves whether or not the kids know the number of days in the months of the year. This causes a lot of errors and discussion. It provides a good opportunity to introduce the famous nursery rhyme: Thirty days hath September...

Thirty days hath September,
April, June, and November;
February has twenty-eight alone,
All the rest have thirty-one,
Excepting leap-year, that's the time
When February's days are twenty-nine.

     The fun thing about this activity is that one's age sounds so BIG! And it keeps changing by the day.


     Additional challenging questions can be posed, depending on the mathematical maturity of the students, that use this basic concept. For example: On what date were you exactly 1000 days old? (That number could be changed to 2000, 3000, etc. to quickly provide more problems at no great cost of preparation time.)

     When I do this with older students, at the middle school level, I make it into a little quiz, giving two invented dates, one that would be appropriate for a parent's birthdate and another for their child's birthdate. After finding the respective ages, in days, of course, I ask them to solve this problem: "The child's age is what percent of the parent's age?"

     After this had been done one year, a student presented me with this poem that she wrote:

Mr. Lee

I told Mr. Lee
to please tell me
what percent of his life
had he spent with his wife


Kevin & Dad Kevin Kevin & Mom


Do you realize that the only time in our lives when we like to get old is when we're kids? If you're less than 10 years old, you're so excited about aging that you think in fractions. How old are you?.... "I'm four and a half" .... You're never 36 and a half .... you're four and a half going on five!

That's the key. You get into your teens, now they can't hold you back. You jump to the next number. How old are you? "I'm gonna be 16." You could be 12, but you're gonna be 16.

And then the greatest day of your life happens .... you become 21. Even the words sound like a ceremony .... you BECOME 21 ... YES!!!

But then you turn 30 .... ooohhh what happened there? Makes you sound like bad milk .... He TURNED, we had to throw him out. There's no fun now.

What's wrong?? What changed?? You BECOME 21, you TURN 30, then you're PUSHING 40 ..... stay over there, it's all slipping away ........

You BECOME 21, you TURN 30, you're PUSHING 40, you REACH 50 ..... and your dreams are gone.

Then you MAKE IT to 60 ..... you didn't think you'd make it!!!!

So you BECOME 21, you TURN 30, you're PUSHING 40, you REACH 50, you MAKE IT to 60 ...... then you build up so much speed you HIT 70!

After that, it's a day by day thing. After that, you HIT Wednesday ....

You get into your 80's, you HIT lunch. My grandmother won't even buy green bananas .... it's an investment you know, and maybe a bad one.

And it doesn't end there .... into the 90's you start going backwards .... I was JUST 92 ...

Then a strange thing happens. If you make it over 100, you become a little kid again .... "I'm 100 and a half!!!!"

--found on the internet.

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