Home / United States / Math Classes / 4th Grade Math / Weight and Capacity in Customary Units

Mass is the amount of matter in an object. Volume or capacity is the space occupied by the object. Measurements of mass and volume are usually expressed in two systems of units: metric system and customary system. Although almost all countries use the metric system of units, the USA uses the customary system of units. The customary units of mass are ounce, pound, and ton, and the customary units of volume are fluid ounce, cup, pint, quart, and gallon....Read MoreRead Less

Based on the **U.S. Customary System**, the customary units come with a set of specific weights and measures, and are used for measuring length, weight, capacity, and temperature.

Weight is the measure of how heavy an object is. The customary units for measuring weight are ounces, pounds, and tons. The conversions for customary units for weight are given in the following chart:

For example, if we have to find out how many ounces there are in 2 tons, we will make the following calculation,

1 ton = 2000 pounds,

So, 2 tons = 2 x 2000

= 4000 pounds

Now, 1 pound = 16 ounces

Thus, 4000 pounds = 16 x 4000

= 64000 ounces

The commonly used units for weight in the U.S. customary system are pounds (lb) and ounces (oz).

Have a look at the following table:

The above table shows us the relationship between the different customary units of weight. As you can see from the table,

1 pound is 16 times 1 ounce, and 1 ton is 2000 times 1 pound. These tables can be useful when converting the units of capacity.

Capacity can be defined as the amount of space occupied by an object. It is also known as ** volume**. The customary units for capacity or volume are fluid ounces, cups, pints, quarts, and gallons.

The conversion chart for the customary units for capacity is as follows:

For example, if we have to convert 4 quarts to cups, we will first calculate,

1 quart = 2 pints

So, 4 quarts = 4 x 2 pints

= 8 pints

Now, 1 pint = 2 cups,

Thus, 8 pints = 8 x 2 cups

= 16 cups

The most commonly used units for capacity or volume in the U.S. customary system are pint and gallon.

Have a look at the following table:

The above table shows us the relationship between the different customary units of capacity. As you can see from the table,

1 gallon is 4 times of 1 quart, 1 quart is 2 times of 1 pint, 1 pint is 2 times of 1 cup, and 1 gallon is 16 times of 1 cup. Once again, this table is useful when converting units of capacity.

**1. Find the number of ounces in 8 pounds.**

**Answer**: As we learned earlier, there are 16 ounces in 1 pound.

Therefore, 8 pounds will have,

8 x 16 = 128 ounces.

So, there are 128 ounces in 8 pounds.

**2. Find the equivalent weight:**

a) 15 lb = ___ oz

b) 6 T = ___ lb

**Answe**r: a) We know that 1 pound = 16 ounces.

Hence, 15 pounds will be equal to 15 x 16 ounces.

15 lb = 15 x 16 oz

= 240 oz

Thus, 15 lb = 240 oz.

b) We know that 1 ton = 2000 pounds.

Hence, 6 tons will be equal to 6 x 2000 pounds.

6 T = 6 x 2000 lb

= 12000 lb

Thus, 6 T = 12000 lb.

**3. A puppy weighs 8 pounds. Calculate its weight in ounces.**

**Answer**: The weight of the puppy = 8 lb

Now we know, 1 lb = 16 oz. Therefore, 8 lb = 8 x 16 oz

8 lb = 8 x 16 oz

= 128 oz

The weight of the puppy is 128 ounces.

**4. Find the number of cups in 5 quarts.**

**Answer**: First, we will find the number of pints, and then we will find the number of cups.

We know that there are 2 pints in 1 quart. Hence, 5 quarts will have 5 x 2 pints.

5 x 2 = 10 pints

Now, there are 2 cups in 1 pint.

Hence, there will be 10 x 2 cups in 10 pints.

10 x 2 = 20 cups

So, there are 20 cups in 5 quarts.

**5. Find the equivalent capacity:**

**a) pints = ____ cups**

**b) 10 gallons = ___ pints**

**Answer**: a) As we know, 1 pint = 2 cups.

Thus, 5 pints will have 5 x 2 cups.

5 pints = 5 x 2 cups

= 10 cups

Thus, 5 pints = 10 cups.

b) Here, we will first find the number of quarts, and from that we will find the number of pints.

We know that 1 gallon = 4 quarts, hence, 10 gallons will be equal to 10 x 4 quarts.

10 gallons = 10 x 4 quarts

= 40 quarts

Now, we have already learned that 1 quart = 2 pints.

Thus, 40 quarts will be equal to 40 x 2 pints.

40 quarts = 40 x 2 pints

= 80 pints

Thus, 10 gallons = 80 pints.

**6. Stanley bought 5 gallons of orange juice, 10 quarts of pineapple juice, and 24 pints of mango juice. Which type of juice was the least quantity that he bought?**

**Answer**: In order to find the least quantity of the type of juice Stanley bought, we will compare the quantities of the three juices that he bought.

For this, we will express the quantities of juice in one common unit, and then compare which type of juice that Stanley bought the least quantity of.

Now we know, 1 gallon = 4 quarts and 1 quart = 2 pints

5 gallons of orange juice = 5 x 4 quarts of orange juice

= 20 quarts of orange juice

Now, 20 quarts of orange juice = 20 x 2 pints of orange juice

= 40 pints of orange juice

Now, we will convert for the pineapple juice.

10 quarts of pineapple juice = 10 x 2 pints of pineapple juice

= 20 pints of pineapple juice

So now we have to compare 40 pints of orange juice, 20 pints of pineapple juice, and 24 pints of mango juice.

As we can see, Stanley bought the least amount of **pineapple juice, which is 20 pints**.

Frequently Asked Questions

The commonly used units for measuring the volume or capacity of objects are gallons, quarts, and pints. For example, Marie bought 5 gallons of milk for her family.

The relationship between pounds, ounces, and tons can be shown as,

1 pound is equivalent to 16 ounces, and 1 ton is equivalent to 2000 pounds. As a result, these units are interconnected with each other.