4,000 minutes

How in the world are going to make up all the snow days we've missed? No one wants to have a shorter summer, so in math we explored the possibility of adding a little extra time on to each day. Here was the math invitation:

Making up our Snow Days 

Our last day of school was supposed to be June 10th but now we must add our missed days to the end of the year. Some people still want to end on June 10th, and rather than having extra days at the end of the year they want to add extra minutes to each day to make up the lost time. Our school day begins at 7:45 and ends at 2:25. So far we have missed 10 days due to snow or rain. How much time have we missed so far? 

What if we added on a little time to each day? How many extra minutes would we need to add each day? What time would school get over? You should plan it so that equal minutes are added on to each day. The earliest the extra time could begin is March 1st. 

You should come up with at least 2 different plans to present to the School Board. You may use a calculator, but make sure that your mathematical thinking is clear for each plan using words, pictures, and numbers. 

To begin, students worked on the first part of the problem trying to figure out how much time we had missed so far. This brought out a variety of strategies and some heated discussions.

Carly used a number line (which we recently used to solve difference problems) to find the number of hours and minutes in one day. Here is her work:

Charlie didn't start by using a number line. He first wrote down 24 x 10. He said this was because there were 24 hours in one day and we missed 10 days. I asked, "Do we go to school for 24 hours a day?" This brought out the eraser. You can see that he then took on more of the number line approach (without the line). He began at 7:45 and added minutes and hours until he arrived at 2:25. He added 15 + 25 to find that it equaled 40 minutes plus the additional five hours and one hour he’d already added on. He then wrote down 5 x 60 and entered it on his calculator. That’s…. 300. Now I need to add 60 more minutes on for the other hour. Ok, 360 minutes plus the 40 minutes equals 400 minutes times 10 days equals 4,000 minutes.

And there you have it! We need to make up 4,000 minutes. Wondering what our plan is?

Here is Clare's plan: (click to make larger)

Take a look at the following album to find nine of our plans.

http://picasaweb.google.com/thirdgradestonypoint/SnowPlans#

Let us know which plan you think sounds like the best.