WCYDWT: Big Baby

via Joshua Sloat, who offers up what is (I believe) our site’s first WCYDWT for upper elementary math students.

1. What questions perplex you about this photo?

Almost nothing went well here, which is what makes this particular moment so valuable for me. The image didn’t urge the question I thought it did, especially when I couldn’t easily clarify its meaning.

Sam Critchlow: how many players on a football team, are football babies bigger?
Chris: How many babies?
Matt: What do the yards and pounds represent?
Peter: what is 24,414 pounds? what is 7908 inches?

The intended question was:

Jazo: how many players?

I have no problem, in these situations, just asking the intended question, but I remind myself to tune my WCYDWT antenna to scan for a better provocation than this one.

2. What is your guess? What is a number you know is too high / too low?

Technical innovation: Google Forms to submit a) the guess and b) the upper / lower bound.

However you handle this, you’d rather not have one student’s developing number sense stunted by another student’s guess. Seriously. When I do this in class, everyone tracks within a standard deviation or two from the first guess, no matter how insane that first guess is. When JB says “the Eiffel Tower is 7 miles tall,” the next guess from AJ is “5 miles.”

3. How can you use math to tell if you’re right or not?

Peter: to know if your guess is right, divide total pounds by your guess

4. Play around. Decide if your guess was too high or too low.

We divided the total pounds (24,214) by one guess of 200 players.

Jazo: 121 pounds? sounds like a weak team
schwartz: less people!

5. Show the answer.

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I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.


  1. Living as I do in the UK, where a football team has 11 players, I would NEVER have guessed 108. But putting that aside, one way of avoiding the “first guess” problem would be to use mini-whiteboards, so everyone writes their guess at the same time and the whole class hold up their boards. The teacher can then see all the guesses at the same time.

  2. I actually took part in this session, Carolann , and made that point in the initial conversation, aside from the fact that the US is one of only 3 countries that still insists on using pounds and inches… (Rule Britannia!, the empire strikes back…).

    Of course, if it had said stones, instead of pounds I might have stood a better chance… ;-)

    I have to admit I do know a wee bit about American football, although if you were Welsh, football would probably be rugby and not soccer, and isn’t the point that feet should be largely involved in kicking, but what do I know about sport anyway.

    Interesting link-in to the ideas of culture that were raised in the ‘pseudo-context’ post and comments, though, and I still like the idea of starting with a baby’s dimensions and working something out from there…

  3. Just a quick addendum to this, about all guesses being made near the first one. It’s human nature, you can really mess with this too, even saying a disconnected number changes guesses.

    Another one is how the brain processes numbers. Get pupils to guess (in two separate halves, in their books)

    1 – 1+2+3+4……..+19+20

    2 – 20+19+18……..+2+1

    No idea how to use this in class.

    Oh, and another thing, some tests are 99% accurate, I mean medical. Given millions of people take some health tests, how many people will be told they have an illness but actually don’t. A scary amount is key, create here to Derren Brown and Dan Goldacre where I borrowed these ideas from.