Running Total

This activity tells the story of a runner named Ted. The number in the box labeled "speed" shows how many feet Ted can run in a second. When you click on the "next second" button, you will see how many seconds Ted has traveled in the box below that button. The box labeled "total" shows you how far Ted has traveled altogether. You can "rewind" the action with the last second to see where Ted was a second ago.

Try moving Ted along for eight seconds. What is the pattern? If Ted ran for 7 seconds at a speed of 4 feet per second, how far would he go? If the pattern isn't clear, try using the "last second" button to rewind and then go forward again with the "next second" button. Or try starting over with a different speed using the "start" button.

Once you think you have the pattern, try answering these questions:

  • How far would Ted go if he ran for 3 seconds at a speed of 8 feet per second?
  • How far would Ted go if he ran for 6 seconds at a speed of 4 feet per second?

Extra challenges

  • If Ted ran a total of 30 feet in six seconds, how fast did he go?
  • If Ted ran a total of 72 feet at a speed of nine feet per second, how many seconds did he run?