Customary Units of Weight
The customary system measures weight in ounces, pounds, and tons with the conversions 1 pound = 16 ounces and 1 ton = 2,000 pounds, as taught in Grade 4 Pengi Math. Unlike metric units that use base-10, customary weight uses irregular factors that students must memorize. A pound is the everyday unit for groceries and body weight; a ton is used for heavy objects like vehicles. Converting between these units requires multiplying or dividing by 16 or 2,000, making estimation and number sense especially important.
Key Concepts
The customary system uses ounces, pounds, and tons to measure weight.
$$1 \text{ pound (lb)} = 16 \text{ ounces (oz)}$$ $$1 \text{ ton (T)} = 2,000 \text{ pounds (lb)}$$.
Common Questions
How many ounces are in a pound?
There are 16 ounces in 1 pound. To convert pounds to ounces, multiply by 16. To convert ounces to pounds, divide by 16.
How many pounds are in a ton?
There are 2,000 pounds in 1 ton. A ton is used to measure very heavy objects like cars, trucks, or large shipments.
What is the difference between ounces and fluid ounces?
Ounces (oz) measure weight/mass. Fluid ounces (fl oz) measure liquid volume/capacity. They are different units that happen to share a similar name.
How do you convert 3 pounds to ounces?
Multiply by 16: 3 × 16 = 48 ounces. Since each pound has 16 ounces, multiply the number of pounds by 16.
When would you use tons vs. pounds in real life?
Pounds are used for everyday items (groceries, people, packages). Tons are used for heavy machinery, vehicles, large quantities of materials like concrete or coal.