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## Tuesday, May 12, 2015

### Common Arithmetic

If our Common Core testing fiasco yields nothing else, I hope it changes the way arithmetic is done in this country.

Scenario: you are told to add these 4 numbers. How do you do it?
If you proceed the traditional "paper and pencil" way, here are your thoughts:
7 + 8 = 15
15 + 6 = 21
21 + 3 = 24Write down 4 under units columnWrite 2 at top of tens column.2 + 4 = 66 + 7 = 1313 + 4 = 1717 + 1 = 18Write down 8 under tens columnWrite 1 at top of hundreds column1 + 3 = 44 + 2 = 6Write down 6 under hundreds column

This took 14 steps, and at no point did you say or even think any number even close to your answer.

Now we will do it left-to-right. Here are the thoughts:
300 + 200 = 500 500 + 40 = 540 540 + 70 = 610 610 + 40 = 650 650 + 10 = 660. 660 + 7 = 667 667 + 8 = 675 675 + 6 = 681 681 +3 = 684 Write down 684

Ten steps, and at each step you were actually thinking numbers that got closer and closer to the final answer.

Why is the first option the most common that people remember? Because single digit arithmetic is the first taught and learned, and it does not vary far from that.

If we treated transportation the way we have treated arithmetic, we would all still be walking.