U.S. Customary units of weight
U.S. customary units of weight introduces Grade 4 students to ounces, pounds, and tons—the three standard weight measurements used in the United States. Key conversions are 16 ounces = 1 pound and 2,000 pounds = 1 ton. Covered in Saxon Math Intermediate 4 Chapter 8, this skill is essential for everyday tasks like reading food labels, measuring ingredients in cooking, and understanding shipping weights in real-world problems.
Key Concepts
The units of weight in the U.S. Customary System are ounces, pounds, and tons. Ounce is abbreviated oz. Pound is abbreviated lb.
A baby elephant weighs 200 pounds. How many ounces is that? $200 \times 16 \text{ oz} = 3200 \text{ oz}$. A small car weighs 1.5 tons. How many pounds is that? $1.5 \times 2000 \text{ lb} = 3000 \text{ lb}$.
Think of these as small, medium, and large weight measurements. An ounce is very light, like a few slices of bread. It takes 16 of those to equal one pound, the weight of a loaf of bread. For really heavy things, like a car, we use tons, which is 2000 pounds!
Common Questions
What are the U.S. customary units of weight?
The U.S. customary units of weight are ounces (oz), pounds (lb), and tons. There are 16 ounces in 1 pound and 2,000 pounds in 1 ton.
How many ounces are in a pound?
There are 16 ounces in 1 pound. To convert pounds to ounces, multiply by 16. For example, 3 pounds equals 3 × 16 = 48 ounces.
How many pounds are in a ton?
There are 2,000 pounds in 1 ton. A small car weighs about 1.5 tons, which equals 3,000 pounds. Tons are used to measure very heavy objects like vehicles, trucks, or large machinery.
When do students learn U.S. customary weight units?
Fourth graders study U.S. customary units of weight in Saxon Math Intermediate 4, Chapter 8, Lessons 71–80. Students learn to convert between ounces, pounds, and tons and apply conversions in word problems.
What is the difference between weight and mass?
Weight measures how heavy an object is due to gravity and is measured in pounds or ounces in the U.S. Mass measures the amount of matter and is measured in grams or kilograms in the metric system. In everyday 4th grade math, weight and mass are often used interchangeably.
How do you convert pounds to tons?
Divide the number of pounds by 2,000 to get tons. For example, 6,000 pounds ÷ 2,000 = 3 tons. This conversion is useful when dealing with very heavy objects.
What are common mistakes when converting customary weight units?
The most common mistake is confusing the conversion factor: students sometimes use 10 or 100 instead of 16 for ounces-to-pounds and 1,000 instead of 2,000 for pounds-to-tons. Always write out the conversion fact before solving.