Dear Students: In the previous two issues I explained the commutative and associative properties of addition and multiplication. Moving right along, we now come to the distributive property! Let's consider the following situation which I am sure many of you have found yourselves in.
It's the day of the big math test. You are quaking in your Nikes. You're just hoping that your teacher, Mr. Kruger, has somehow forgotten about the test. (After all, you did.) Mr. Kruger marches into class carrying a thick sheaf of papers still hot from the copier. Stalking over to your desk, he towers over you.
"Edward!" he barks like a Doberman.
"Y-e-s-s-s-s, s-i-r?" you quaver. Your stomach feels like you ate cold pizza for lunch. In fact, you did eat cold pizza for lunch.
"Would you please distribute the math test for me?" Mr Kruger actually sounds friendly.
"Yes, sir!" you exclaim jumping up from your seat. Maybe Mr. Kruger will take into account your prompt and enthusiastic helpfulness when he grades your paper.
Walking up and down the rows, you place one test on each desk. (You certainly aren't going to keep them all for yourself.) When you have finished, you return to your seat.
"Thank you, Edward," Mr. Kruger says politely. "You did a very nice job of distributing those math tests."
"No problem," you say nonchalantly.
The distributive property is a little like passing out the math tests. Take a look at the following equation.
You've got a choice. You can first do the addition, (4 + 2), and get 6; then multiply 3 x 6 and get 18.
Or, you can pass out, or distribute, the 3 over the 4 and the 2 and make up two little multiplication problems. Do the multiplication first, then add the products. Either way you do it, you still get 18.
Usually, we write the little multiplication problems horizontally, like this:
So, there you have it. Next time you run into the distributive property, remember to pass out the multiplication over the addition. (Next time you have a math test, remember to study!)
Read more about the properties of math!
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"Ask Lois Terms" © 1997 Lindsay-Livingston