In which we determine how many grapefruits and avocados there, and observe the brilliance of young children.

# Results for "how do you know?"

## Does the Earth have an end?

Talking Math with Other People's Kids Month continues... A while back, Rafranz Davis reported a conversation on her blog. She writes frequently about the adventures she has with her nephew Braeden. I asked, and she gave me permission to remix a conversation she and...

## Doll years

Out of the blue on our recent camping trip, Tabitha had an announcement for me. Tabitha (6 years old): I am 12 in doll years and Griffy is 16 in doll years. Her brother Griffin is 9. T: So how old are you in doll years, Daddy?Me: Well, how do doll years work? T: Well,...

## Cold snap

Below zero temperatures lead to comparisons of positive and negative numbers, and the solution to 4 – (-1).

## Cookies under constraints

A propos of nothing one day, I ask Griffin (9 years old at the time, finishing up fourth grade) a question. Me: Griff, imagine you are baking cookies and you need $latex \frac{3}{4}$ cup of sugar, but you only have a $latex \frac{1}{2}$ cup measure. How would you...

## Peeps

This is one of my favorite tasks in recent years. The idea is that we will compare two sets of Peeps. Are there more of one color or the other? There is so much fun to be had counting Peeps. Now that Valentine's Day is past, Peeps (a common Easter candy) are back in...

## Legos

The dirty little secret about Legos is how very many pieces there are to be cleaned up after building. And how very ugly the clean-up battle can become. I try to keep calm. I try to turn the clean-up battle into math talk from time to time. Here is how it played out a...

## Patterns on the multiplication machine

Tabitha (6 years old) has been playing with the multiplication machine off and on for a few months now. We have never once used it for learning multiplication facts, but we have had a ton of math-learning fun with it. Recently, she carefully did...

## The meanings of division

I was talking with Griffin one day when he was in third grade. Me: Do you know what $latex 12\div 2$ is?Griffin (8 years old): 6Me: How do you know that's right?G: 2 times 6 is 12. Me: What about $latex 26 \div 2$?G: 13Me: How do you know...

## Summer project (2 of 3): Measuring the Hill

This post follows up on a conversation I had with Griffin a while back about the height of the Giant Slide at the Minnesota State Fair. Our house in St Paul sits on top of an odd hill; higher than others around it. Historical reasons for this are murky but it makes...