My Favorite Thing from Yesterday (4) - Cal Used His Own Brain

Cal’s a huge fan of math, and he’s pretty good at it.  We try to contain his practicing of math to addition and subtraction to be sure that he understands those concepts before trying to tackle multiplication and division; but it doesn’t always work, and we find ourselves either assisting him with multiplication or confirming his multiplication math sentences.

What started as, “Mommy, what’s 30 times 10?” has evolved into “Mommy, I know what 300,000 times 10 is… 3,000,000,” followed by an “I know that’s right” grin.

I don’t believe he understands the multiplication concept so much as the trick to figuring some of it out.  I told him once or twice that any number times ten is the number with a zero on the end of it – 3 times 10 is 30… 29 times 10 is 290… and so on.  He caught on quickly and can do it with smaller and larger numbers.

The fact that he already gets that there are tricks to doing math is pretty cool.  I had the pleasure of taking him to his swimming lesson last night.  On the way there, we had this conversation:

“Mommy, I know what 30 plus 19 is,” Cal stated from his car seat.

“Oh, yeah, what’s 30 plus 19?” I asked him from the driver’s seat.

“49,” he responded

“That’s right, Cal,” I confirmed.  That Cal knew this wasn’t surprising to me, so I thought I’d pose a more difficult math equation for him, one that maybe he’d be able to figure out.  “Okay, Cal, I have another one for you.  Can you tell me what 29 plus 19 is?  See if you can figure that out.”

Cal thought for a bit and then exclaimed, “48!”

This garnered an excited, “That’s right, Cal!  That’s excellent!  How did you figure that out?” from me.

Cal thought for a few seconds, “Hmm… I don’t know.”

Hmm.  I followed by saying something to the effect of “Well, maybe you figured that 29 is one less than 30 and just subtracted one from 49.  That’s how I would do it quickly.”

Cal then attempted to repeat what I had said, as if that’s the logic that he used.  Maybe it was.  All I know is, we tried a few more math equations using numbers around 19 and 30, and he got them all right.

As we neared swimming, Cal said, “Mommy, I figured that out using my own brain.”

This amused me.  “Well, who else’s brain would you have used?  My brain?”

“No,” he replied.

“And why wouldn’t you have used my brain?” I asked, fully expecting him to say that it’s because it’s attached to my body, not his.  That’s what I would have said, anyway.

“Because we would have had to cut your head off and cut my head off,” he answered. He added something about then do something with them and each of our bodies, I can’t recall exactly what.  Yikes.

And that story, particularly with that ending, is my favorite thing from yesterday.