## Tuesday, May 11, 2010

### Late, Later, Latest.

Late: Overdue, tardy, behind schedule. Formerly holding a job or position. Formerly alive.

Don't worry, I'm neither formerly employed nor formerly alive. I'm just late with the blog today.

Late is a state of mind. I hate to be late, so I am usually early. Last week I had a conversation with my sister about this. She said something to the effect that people who are always on time are boring. I disagreed (I had to!) and said we "on-timers" are just a bit more intense, and furthermore, we "watch the time" and try to treat other people and their time with respect. I got nowhere with this argument, but then that's the nature of brother/sister relationships (perhaps family relationships in general).

Aren't family photos fun?

Here are some of my relatives. Some of them are late, as in formerly alive, but we still remember them.

What does all this have to do with math?

Math is the subject area in schools that is responsible for teaching time.

We teach time - seconds, minutes, hours, days, etc. We explain how 12- and 24-hour clocks work. Then we teach more complicated time scenarios with examples like this:

Q: Kathy and Mike have agreed to meet their mother for lunch at 1 pm. Kathy knew it would take her 30 minutes to drive to the restaurant. What time does she need to leave her house in order to reach the restaurant on time?

A: 12:30 pm.

Feel free to use any information from the first problem in the second problem:

Q: Kathy and Mike have lunch then walk into the theater next door to see a movie. The lunch takes 1 hour and the movie runs for 2 hours and 15 minutes.  If they met for lunch at 1 pm, what is the earliest time that Kathy could expect to return to her house?

A: Lunch = 1 hour + Movie = 2.25 hours + Driving = .5 hours = total of 3.75 hours (3 hrs 45 min)
3:45 added to 1:00 pm = 4:45 pm

Once we've figured out this sort of thing, then we can talk about time zones. If you want to call your mom on Mother's Day and she's in Cleveland while you are in Phoenix, you better know when to call!

We introduce longer time intervals. We explore the calendar. So we can solve problems like this:

Q: Kathy was born on May 15, 1950. When is her next birthday and how old will she be?

A: May 15, 2010 (this coming Saturday) she will be __ years old. Happy Birthday Kathy!

And finally students have the ability to tackle questions like this:

Q:  Mike was born 15 months, 16 days and 17 minutes after Kathy. When is his next birthday, how old will he be, and what day of the week will it be?

A: I am not telling.