Customary Units of Length
Customary Units of Length is a Grade 4 math skill from Pengi Math that teaches students the standard US measurement units for length — inches, feet, yards, and miles — and the conversion factors between them: 12 inches = 1 foot, 3 feet = 1 yard, 1,760 yards = 1 mile. Students learn to convert between units by multiplying (smaller to larger) or dividing (larger to smaller). Mastering these conversions in 4th grade enables solving multi-step measurement word problems and understanding real-world measurements.
Key Concepts
Property The primary customary units of length are the inch, foot, yard, and mile. $$1 \text{ foot (ft)} = 12 \text{ inches (in)}$$ $$1 \text{ yard (yd)} = 3 \text{ feet (ft)}$$ $$1 \text{ mile (mi)} = 1,760 \text{ yards (yd)} = 5,280 \text{ feet (ft)}$$.
Examples To convert 5 feet to inches: $5 \text{ ft} \times 12 \frac{\text{in}}{\text{ft}} = 60 \text{ in}$ To convert 21 feet to yards: $21 \text{ ft} \div 3 \frac{\text{ft}}{\text{yd}} = 7 \text{ yd}$ To convert 2 miles to feet: $2 \text{ mi} \times 5,280 \frac{\text{ft}}{\text{mi}} = 10,560 \text{ ft}$.
Explanation Length in the customary system is measured using inches, feet, yards, and miles. To convert from a larger unit to a smaller unit, you multiply by the appropriate conversion factor. For example, to change feet to inches, you multiply by 12. To convert from a smaller unit to a larger unit, you divide.
Common Questions
What are the customary units of length?
The customary units of length from smallest to largest are: inch (in), foot (ft), yard (yd), and mile (mi). The conversion facts are: 12 inches = 1 foot, 3 feet = 1 yard, and 5,280 feet (or 1,760 yards) = 1 mile.
How many inches are in a foot?
There are 12 inches in 1 foot. To convert feet to inches, multiply by 12. For example, 4 feet = 4 × 12 = 48 inches. To convert inches to feet, divide by 12. For example, 36 inches = 36 ÷ 12 = 3 feet.
How many feet are in a yard?
There are 3 feet in 1 yard. To convert yards to feet, multiply by 3. For example, 5 yards = 5 × 3 = 15 feet. To convert feet to yards, divide by 3. For example, 21 feet = 21 ÷ 3 = 7 yards.
When should I use inches vs feet vs yards vs miles?
Inches are used for small objects like a pencil length. Feet are used for room dimensions and human height. Yards are used for football fields and fabric. Miles are used for driving distances and geographic measurements. Choose the unit that gives a reasonably sized number.
When do 4th graders learn customary units of length?
Customary units of length are covered in 4th grade math. Pengi Math Grade 4 teaches students all four units (inch, foot, yard, mile) and their conversion relationships, building toward solving multi-step measurement word problems.
How do you convert 2 yards to inches?
First convert yards to feet: 2 yards × 3 = 6 feet. Then convert feet to inches: 6 feet × 12 = 72 inches. Or multiply directly: 2 yards × 36 inches/yard = 72 inches (since 1 yard = 3 feet = 36 inches).
Which textbook covers customary units of length for 4th grade?
Pengi Math Grade 4 covers customary units of length with conversion facts and practice applying them to measurement problems, building fluency with the US customary measurement system.