C) The unit factor conversion method of problem solving As an example of how to use the unit conversion factor method to solve a problem, we will use the following problem: "An experiment is done to see the health effect of large amounts of aspirin on rats. Each rat gets 22 grams of aspirin. If 60 rats are used in the experiment, bow many grams of aspirin will be used?" Step 1: Write the answer unit: Read the problem and find what units the answer must have. The answer units are usually the units after the words "how many" or "how much." In our example, the problem asks "bow many grams of aspirin" so grams of aspirin are the answer unit. Write t= grams aspirin" on the right side of the paper: Step 2: Find a unit conversion factor that involves the answer unit: Read the problem and find a sentence that relates the answer unit to something else. In our examplc, one sentence reads "Each rat gets 22 grams of aspirin." This sentence relates the answer unit (grams of aspirin) to something else (rats). Step 3: Write a unit conversion factor based on the sentence. The unit conversion factor must have the answer units on the top. 22 grams aspirin = grams aspirin 1rat Step 4: Find a value in the problem that has the same units that appear on the botrom of the unit conversion factor. In our problem, the units that appear on the bottom of the unit conversion factor are "rat," so look for a value in the problem that relates to rats. "If 60 rats are used in the experiment..." is the value statement relating to rats. 60 rats x22 grams aspirin = grams aspirin I rat Step 5: Check to see that the units cancel. This means that for each unit on the bottom of a fraction, you must find the same unit at the top of a fraction. Units that are not shown as fractions (like " 60 rats" in this problem) are considered to be at the top of a fraction. You can check that the units cancel by writing a slash through each unit that appears at the bottom and at the top of a fraction. In our example, the rat units cancel. 60ratsy1nt22gramsaspirin=gramsaspirin C) The unit factor conversion method of problem solving As an example of how to use the unit conversion factor method to solve a problem, we will use the following problem: "An experiment is done to see the health effect of large amounts of aspirin on rats. Each rat gets 22 grams of aspirin. If 60 rats are used in the experiment, bow many grams of aspirin will be used?" Step 1: Write the answer unit: Read the problem and find what units the answer must have. The answer units are usually the units after the words "how many" or "how much." In our example, the problem asks "bow many grams of aspirin" so grams of aspirin are the answer unit. Write t= grams aspirin" on the right side of the paper: Step 2: Find a unit conversion factor that involves the answer unit: Read the problem and find a sentence that relates the answer unit to something else. In our examplc, one sentence reads "Each rat gets 22 grams of aspirin." This sentence relates the answer unit (grams of aspirin) to something else (rats). Step 3: Write a unit conversion factor based on the sentence. The unit conversion factor must have the answer units on the top. 22 grams aspirin = grams aspirin 1rat Step 4: Find a value in the problem that has the same units that appear on the botrom of the unit conversion factor. In our problem, the units that appear on the bottom of the unit conversion factor are "rat," so look for a value in the problem that relates to rats. "If 60 rats are used in the experiment..." is the value statement relating to rats. 60 rats x22 grams aspirin = grams aspirin I rat Step 5: Check to see that the units cancel. This means that for each unit on the bottom of a fraction, you must find the same unit at the top of a fraction. Units that are not shown as fractions (like " 60 rats" in this problem) are considered to be at the top of a fraction. You can check that the units cancel by writing a slash through each unit that appears at the bottom and at the top of a fraction. In our example, the rat units cancel. 60ratsy1nt22gramsaspirin=gramsaspirin