Grade 3 · Math · Lesson 19

Measure Length, Mass, and Capacity

Measurement lets us describe the world in numbers. We measure three key attributes: length (how long), mass (how heavy), and capacity (how much a container holds). In the US we use two systems side by side: customary units (inches, pounds, cups) and metric units (centimeters, grams, liters). Both are correct — pick the unit that fits the size of the object.

What this lesson teaches

1Name the right tool and a US customary and metric unit for length, mass, and capacity
2Read a measurement from a ruler, scale, or measuring cup in both unit systems
3Choose the most sensible US customary or metric unit when estimating a real-life measurement

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