Arithmetic Grade Four

Lesson One hundred and forty-seven: METRIC VOLUME and WEIGHT

English units for weight (or mass) are ounces, pounds, and tons. Metric units for weight (or mass) are milligrams (mg), grams (g), and kilograms (kg). You could also speak of centigrams, but you don't hear that one very often. Here are the basic conversions for grams: 


            1000 mg = 1 g
            1000 g = 1 kg
One place you will see miligrams used a lot is on vitamin pill labels. For instance, a bottle of vitamin C might tell you that each vitamin C pill contains 500 mg of vitamin C. A mineral supplement label might tell you that each pill contains 333 mg of calcium, 133 mg of magnesium, and 5 mg of zinc. (These are actual numbers taken from an actual vitamin pill label, by the way.)

You are likely to see grams used on food product labels. For instance, consider these food items: 

 
   FOOD ITEM          |     GRAMS       |      POUNDS / OUNCES
 ---------------------|-----------------|------------------------
  1) banana muffins   |     272 g       |     9.6 oz
  2) wheat cereal     |     538.6 g     |    1 lb 3 oz
  3) mac and cheese   |     206 g       |     7.25 oz
                      |                 |

NOTE: Remember that ounces used for weight are different from ounces used for volume.
Kilograms are used for heavier items. One kilogram is equal to 2.2 pounds. For instance, a 7.5 pound exercise weight is also labeled in kilograms (3.4 kg).

Here are a few conversion problems involving mg, g, and kg. 


  1) Convert 2 grams into milligrams.
   
     SOLUTION: To convert grams to milligrams multiply by 1000.
               (2 x 1000 = 2000)

     ANSWER: 2000 mg

  2) Convert 2 kilograms into grams.

     SOLUTION: To convert kilograms to grams multiply by 1000.
               (2 x 1000 = 2000)

     ANSWER: 2000 g

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