You can find the 70+ entries under the B2N section. Let me walk you through how I use Entry #1.
Step 1: Notice & Wonder
I project the two images and set a timer for 30 seconds. No writing yet—just quiet thinking.
Step 2: Estimation & Discussion
I say:
Before I show you the actual speeds, talk with a neighbor: What do you think their speeds might be? Estimate in miles per hour.
Students write down their guesses in their journals—I give them one minute.
Then I randomly call on two students to share their snail estimates and two more for the jet. I write the estimates on the board.
Step 3: Reveal the Speeds
I show the snail’s speed and ask:
Who had the closest guess?
This is a great moment to reinforce decimal comparison.
Then I reveal the jet’s speed and repeat the question.
I sometimes add related trivia—like the average speed of a commercial airplane.
Step 4: Abstract the Context
This next step is important—and a big time-saver.
To reduce stress and focus on the math, I say:
Let’s say the snail’s speed is A, the jet’s speed is B, and the distance across the U.S. is C = 2,800 miles.
Step 5: Set Up the Math
I prompt students:
With your partner, discuss what calculation(s) you would do to find out how long it takes each object to travel across the U.S. Use just the letters—like A × C or C ÷ A.
I set the timer for one minute.
Then I randomly call on one group to share their solution idea. I write it on the board and ask:
Who has a different solution?
I keep adding to the list until all reasonable approaches are captured. (Usually just two or three.)
Step 6: Solve & Discuss Units
I pull out a calculator to evaluate the expressions using the actual values. Then I ask the student who shared each one:
What unit should your answer have?
We discuss reasonableness and make sense of the outcomes.
I’m proud of this routine because it allows for:
Interesting facts
Estimation
Student discourse
Proportional reasoning
Unit rates
Dimensional analysis
Please share this resource widely. And if you try it—I’d love to hear how it goes.