To convert any given number of pounds into grams, you must know the proper conversion factor between pounds and grams, and how to set up and solve a basic unit conversion problem. The conversion factor between pounds and grams is .002205 pounds for every gram, or 453.5 grams for every pound. These should be written as fractions when solving a conversion problem (1 g/.002205 lbs or 453.5 g/1 lbs).
- Write the given information and conversion factor
Set up the information like a multiplication problem, starting with the unit you want to convert from, which in this case is four pounds. Next, multiply it by the conversion factor, written as a fraction. It should look like this: 4 lbs x 1 g/.002205 lbs or 4 lbs x 453.5 g/1 lbs.
- Cancel the common units
Since the pound unit appears in the opposing numerator and denominator of fractions in a multiplication problem, they can be cancelled, which assures that only the desired unit you want to arrive at (grams) remains. In this case, 4 lbs is equal to 4 lbs/1, making 4 lbs the numerator in a fraction. It should look like this now: 4 x 1 g/.002205 or 4 x 453.5 g.
Simply apply the math and solve the problem, ensuring that you carry over the units with the numerical answer. Divide 4 by .002205 or multiply it by 453.5 to arrive at approximately 1814 grams.