GED Measurements: Adding Different Metric Units

Hey, all. I know math is what keeps a lot of people from their GED, so keep those math questions comin’, so I can get you the answers! Here’s a good question about the metric system from a GED student:

I have a question about the metric system. How do I add Grams and kilograms and milligrams, and decagrams together?

Ex.
Add: 3.45g, 0.06kg, 0.67g, 690mg, 2dg?

Hey! Yeah, excellent question. I got a article about the metric system you might wanna take a look at, to get some metric system basics… it’s at: http://www.passged.com/student_blogs/curtis/2008/07/29/ged-math-the-metric-system/

You can see the prefixes… beginnings of the words… all have meanings in the metric system. So, “grams” is just the basic measure of weight… “kilograms” is 1000 grams (kilo- = 1000), “milligrams” is 1/1000th of a gram (milli- = .001), and “decagrams” is 10 grams (deca- = 10).

First thing you wanna ask is, what do you want the answer in? Grams? Or something else? Usually the question’ll tell you, but if it don’t, choose one. In your question, I’m goin for the basic measure… grams. Two numbers is already in grams, so that makes it easier.

3.45g + 0.06kg + 0.67g + 690mg + 2dg =

So, once you figure out what you want the answer in, you gotta convert all the measures to the same thing… whatever you want the answer in… in this case, grams.

The cool thing about the metric system is, all you got to do to convert is move the decimal places. So, to change 0.06kg into grams, you multiply by 1000… which is the same as moving the decimal 3 places to the right. (You can remember cuz 1000 got 3 zeros.) So, 0.06kg is really 60 grams…

3.45g + 0.06kg + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 690mg + 2dg

So, the next one to change is 690mg. Same deal. “Milli” means 1/1000th, or .001 of a gram. So, you divide 690 by 1000 (or multiply by .001–hey, it’s the same thing!) But the easy part is, either one means moving the decimal 3 to the left (3 zeros in 1/1000, but since it’s a fraction, the decimal goes to the left instead of the right). So, 690mg = .69 grams

3.45g + 0.06kg + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 0.69g + 2dg

One more… decagrams. You guessed it. Multiply by 10. 2×10=20. Well, it’s the same thing… move the decimal point (the invisible one at the end of any whole number, like 2 = 2.0) over one to the right, cuz 10 got 1 zero. So, 2dg = 20 grams.

3.45g + 0.06kg + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 690mg + 2dg = 2.45g + 60g + 0.67g + 0.69g + 2dg = 2.45g + 60g + 0.67g + 0.69g + 20g

Now, all you got is grams. So… jus’ add. 2.45 + 60 = 62.45 + .67 = 63.12 + .69 = 63.81 + 20 = 83.81

Remember, it’s in grams… so that’s 83.81 grams.

Any time somthin’s in different measures (inches and feet, grams and kilograms, ounces and pounds, whatever), the first thing you gotta do is make all the measurements the same… an’ to make your life easier, make ‘em all whatever you want the answer in. Then on, it’s all basic math!

Good studyin’!

Curtis

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