Medical Math

• Converting one system of measurement to another system of measurement requires that you know, or you are able to look up, the equivalent unit of measurement for the different systems of measurement.

• For example, if you have to convert km to miles, you will have to know how many kms in a mile or how many miles there are in a km; if you have to convert grains to grams, you will have to know how many grains in a gram or how many grams there are in a grain; and if you have to convert mg to grains, you will have to know how many mgs in a grain or how many grains there are in a mg.

• Once you know the conversion equivalent, you would set up and solve an equation that can be done in a number of different ways, however, for the purpose of this review, we will use ratio and proportion as you have learned earlier.

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Here is an example:

• If there are 2.2 pounds in one kilogram, how many kilograms are there in 160 pounds?

• Pounds : Kilograms = Pounds : Kilograms

• 2.2 Pounds : 1 Kilograms = 160 Pounds : x Kilograms

• 2.2 x = 160

• x = 160 / 2.2

• x = 72.73 kg rounded off to the nearest hundredth

• Answer - 72.73 kg is equivalent to 160 pounds

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Here is another example:

• If there are 2.2 pounds in one kilogram, how many pounds are there in 32 kg?

• Pounds : Kilograms = Pounds : Kilograms

• 2.2 Pounds : 1 Kilograms = x Pounds : 32 Kilograms

• x = 32 x 2.2

• x = 70.4 pounds

• Answer - 70.4 pounds is equivalent to 32 kg

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Here are other conversion problems examples.

Example 1:

• How many mg are there in 34 grains? (1 gr = 60 mg)?

• Mg : Gr = Mg : Gr

• 60 mg : 1 gr = x mg : 34 gr

• x = 60 x 34

• x = 2040 mg

• Answer - 2040 mg is equivalent to 34 gr

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Example 2:

• How many mL are there in 4 tablespoons? (1 tbsp. = 15 mL)

• Tbsp. : mL = Tbsp. : mL

• 1 tbsp. : 15 mL = 4 tbsp. : x mL

• x = 15 x 4

• x = 60 mL

• Answer - 60 mL is equivalent to 4 tablespoons.

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Example 3:

• How many mL are there in 4 teaspoon? (1 tsp = 5 mL)

• Tsp : mL = Tsp : mL

• 1 tsp : 5 mL = 4 tsp : x mL

• x = 5 x 4

• x = 20 mL

• Answer - 20 mL is equivalent to 4 teaspoons.

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Example 4:

• How many grams are there in 4 pounds? (1 lb. = 454 g)

• Pounds : Grams = Pounds : Grams

• 1 lb. : 454 g = 4 lbs. : x g

• x = 454 x 4

• x = 116 g

• Answer - 116 g is equivalent to 4 pounds.

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Example 5:

• How many mL are there in 4.4 liters? (1000 mL = 1 Liter)

• mL : Liters = mL : Liters

• 1000 mL : 1 liter = x mL : x 4.4 liters

• x = 1000 x 4.4

• x = 4400 mL

• Answer  4400 mL is equivalent to 4.4 liters.