How to Use Multiplication to Compare Customary Units

Here are some key conversions that typically require multiplication or division:

1. Length:
   • 1 foot = 12 inches
   • 1 yard = 3 feet
   • 1 mile = 5,280 feet
2. Weight:
   • 1 pound = 16 ounces
   • 1 ton = 2,000 pounds
3. Volume:
   • 1 cup = 8 fluid ounces
   • 1 pint = 2 cups
   • 1 quart = 2 pints
   • 1 gallon = 4 quarts

We use multiplication when we convert from a larger unit to a smaller unit. For example, if you have a length in feet and want to find out how many inches it is, you would multiply the number of feet by 12.

A Step-by-step Guide to Using Multiplication to Compare Customary Units

Let’s go through a step-by-step guide for using multiplication to compare customary units of measurement.

Step 1: Understand the Problem

Read the problem carefully. Identify the units you’re starting with (your input units) and the units you want to end up with (your output units).

Step 2: Recall the Conversion Factor

Remember or look up the conversion factor between these units. A conversion factor is the number you use to convert from one unit to another. For example, the conversion factor from feet to inches is 12 because there are 12 inches in a foot.

Step 3: Set Up Your Equation

Write an equation to show your conversion. This will typically look like this:

(Output units) = (Input value) \(\times\) (Conversion factor)

If you’re converting from a larger unit to a smaller unit (like feet to inches or pounds to ounces), you’ll multiply.

Step 4: Do the Math

Multiply your input value by the conversion factor to get your output value.

Step 5: Check Your Work

Make sure your answer makes sense. For example, if you’re converting from a larger unit to a smaller unit, your output value should be larger than your input value.