12 Square Inches vs 12 Inches Squared

In RS2 Level C, Lesson 109, the child is introduced to measuring area. After a problem of square inches is discussed, the lesson shows the child how to write 12 square inches: 12 in². Then, there’s an explanation on the side that reads:

Be sure to read 12 in² as “twelve square inches.” Avoid saying “twelve inches squared,” which has an entirely different meaning.

Kirsten sent us an email and wanted a more complete explanation of the different meaning of twelve inches squared. Good question, Kirsten!

Ok. I will confess I had to go to Dr. Cotter to clarify this for both of us! So here it is.

First, if you say “12 inches,” that’s easy. It’s just 12 inches!

When we have an area 4 inches wide by 3 inches tall, it’s 12 square inches.

It’s a measurement of area, indicated by the word “square” and the little ². The measurement for the area under discussion is inches. Hence the name “12 square inches,” written by “12 in².”

Now, if you say “12 squared,” it calculates to 144, right?

12² = 144

Extending that, if you say “12 inches squared,” it’s a logical process to square 12 inches, giving us 144 inches.

So “12 inches squared” is a long distance of 144 inches and “12 square inches” is a 3 by 4 inch area. Or 2 by 6. Or 1 by 12. You get my drift.

That’s why it’s so important to read 12 in² as twelve square inches!

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