Grade 4 · Math · Lesson 28

Understand Volume Basics

Volume tells us how much space is inside a 3D solid. Unlike area (which measures a flat surface), volume measures the space that fills a three-dimensional object. Volume is always measured in CUBIC units: cubic inches (in³ or cu in) and cubic feet (ft³ or cu ft) in US customary, or cubic centimeters (cm³) and cubic meters (m³) in metric. Liquids use a separate set of units: cups, pints, quarts, gallons in customary; milliliters and liters in metric.

What this lesson teaches

1Define volume as the amount of space inside a 3D shape, measured in cubic units (in³, ft³, cm³, m³)
2Calculate solid volume using V = l × w × h in either customary or metric units
3Identify liquid-volume units in both systems (cups, pints, quarts, gallons; mL and L)
4Distinguish between 2D shapes and 3D solids

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