Customary Units
Units of Length
- Inch (in): Smallest common unit
- Foot (ft): 1 ft = 12 in
- Yard (yd): 1 yd = 3 ft = 36 in
- Mile (mi): 1 mi = 1,760 yd = 5,280 ft
Units of Liquid Volume
- Fluid ounce (fl oz): Smallest common unit
- Cup (c): 1 c = 8 fl oz
- Pint (pt): 1 pt = 2 c = 16 fl oz
- Quart (qt): 1 qt = 2 pt = 4 c = 32 fl oz
- Gallon (gal): 1 gal = 4 qt = 8 pt = 16 c = 128 fl oz
Units of Weight
- Ounce (oz): Smallest common unit
- Pound (lb): 1 lb = 16 oz
- Ton (T): 1 T = 2,000 lb
Perimeter, Area, and Volume
- Perimeter: Distance around a 2D shape (e.g., rectangle: P = 2l + 2w)
- Area: Surface covered (e.g., rectangle: A = l × w)
- Volume of a Solid: Space inside (e.g., box: V = l × w × h)
Time
- Seconds, Minutes, Hours, Days, Weeks, Months, Years
- 1 min = 60 sec; 1 hr = 60 min; 1 day = 24 hr; 1 week = 7 days
Temperature
- Measured in degrees Fahrenheit (°F) in the U.S.
Metric Units
Units of Length
- Millimeter (mm): 1/1,000 meter
- Centimeter (cm): 1/100 meter
- Meter (m): Base unit
- Kilometer (km): 1,000 meters
Units of Liquid Volume
- Milliliter (mL): 1/1,000 liter
- Liter (L): Base unit
Units of Mass
- Milligram (mg): 1/1,000 gram
- Gram (g): Base unit
- Kilogram (kg): 1,000 grams
- Tonne (t): 1,000 kilograms
Perimeter, Area, and Volume
- Perimeter: e.g., rectangle: P = 2l + 2w (units: meters, centimeters, etc.)
- Area: e.g., rectangle: A = l × w (units: m², cm², etc.)
- Volume of a Solid: e.g., box: V = l × w × h (units: m³, cm³, etc.)
Temperature
- Measured in degrees Celsius (°C)
Unit Conversion
Changing from Customary Units to Metric Units
- 1 inch ≈ 2.54 centimeters
- 1 foot ≈ 0.3048 meter
- 1 yard ≈ 0.9144 meter
- 1 mile ≈ 1.609 kilometers
- 1 fluid ounce ≈ 29.57 milliliters
- 1 gallon ≈ 3.785 liters
- 1 ounce ≈ 28.35 grams
- 1 pound ≈ 0.454 kilogram
- 1 ton ≈ 0.907 metric ton
- °F to °C: (°F - 32) × 5/9
Changing from Metric Units to Customary Units
- 1 centimeter ≈ 0.3937 inch
- 1 meter ≈ 3.281 feet
- 1 kilometer ≈ 0.6214 mile
- 1 milliliter ≈ 0.0338 fluid ounce
- 1 liter ≈ 0.2642 gallon
- 1 gram ≈ 0.0353 ounce
- 1 kilogram ≈ 2.205 pounds
- 1 metric ton ≈ 1.102 tons
- °C to °F: (°C × 9/5) + 32
Examples
1. Customary Length
If a table is 4 feet long, how many inches is that?
Solution: 4 ft × 12 in/ft = 48 inches
2. Metric Mass
A bag of rice weighs 2 kg. How many grams is that?
Solution: 2 kg × 1,000 g/kg = 2,000 grams
3. Customary Volume
How many quarts are in 2 gallons?
Solution: 2 gal × 4 qt/gal = 8 quarts
4. Metric Area
What is the area of a rectangle 5 m long and 3 m wide?
Solution: 5 m × 3 m = 15 m²
5. Temperature Conversion
Convert 68°F to Celsius:
Solution: (68 - 32) × 5/9 = 36 × 5/9 ≈ 20°C
Pre-Test: Measurements and Units
Questions & Answers
Complete the Pre-Test. Any questions you miss will appear here with answers and explanations.