Sunday, June 8, 2014

Why the new math works

The "new math" works. I have undeniable proof in the form of a personal anecdote, which we all know is the most irrefutable kind of evidence.

On the first day of summer vacation, when the slide begins and kids lose all the knowledge they gained in the academic year, I realized I was almost out of gas. Again. My Honda Odyssey never beeps to tell me so I'm always surprised to realize I only have 7 miles left.

I rushed to a local gas station and my nine-year old watched the gallon tally climb. It stopped at 18 gallons.

"How many miles does that mean?" he asked.

"Well, my engine gets about 20 miles per gallon," I replied. "So how would we figure that out?"

When I asked that question, I expected him to name the process, not give me an answer. I thought he would say, "We'd multiply 20 by 18." I certainly can't do that math problem in my head and can't use my iPhone calculator while driving.

But then New Math happened.

"We could do 18 times five, then take that answer and either add four of those or multiply that by 4," my son answered. "So, let's see. 18 times 5 is 90. And that four times is 360."

I glanced at my van dash, which now read that I had 356 miles in my tank. I blinked. He nailed it. I was stunned.

"You're right!" I exclaimed. "The van computer estimated 356 miles."

He beamed.

His approach was elegant. Simple. If only someone had helped me learn to tackle math that way. Wait- someone is! My nine-year old.

Thanks math teachers. Thanks new math.

Third Grade Multiplication Master