Lesson 11 of 12
📏 Measurement
What You'll Learn
- Measure lengths in inches and centimeters
- Know when to use inches, feet, or yards
- Compare and order lengths
Units of Length
We measure length using standard units so everyone gets the same answer:
- Inch (in) — about the length of your thumb tip. Good for small objects.
- Foot (ft) — 12 inches. About the length of a standard ruler. Good for rooms and people's height.
- Yard (yd) — 3 feet = 36 inches. About the height of a kitchen counter. Good for fabric or football fields.
Pick the Right Unit
A caterpillar? Inches. A classroom? Feet. A football field? Yards. Always ask: “Would I need thousands of the small unit? Then go bigger!”
How to Use a Ruler
- Line up the 0 end of the ruler with the start of the object
- Read where the object ends on the ruler
- That number is the measurement in inches
Practice with the ruler below. Each object is placed at the 0 mark — just read where it ends!
Quick Check
1. A pencil is 7 inches long. How many inches longer is it than a 4-inch eraser?
2. How many inches are in 1 foot?
3. Which unit is best for measuring your height?