1/15
00:00

EE.2 Convert and compare metric units of mass

Loading questions...

Understanding metric units of mass

Mass is the amount of matter in an object. In the metric system, we use grams and kilograms to measure mass.

Examples:
  • A paperclip has a mass of about 1 gram
  • A textbook has a mass of about 1 kilogram
  • A liter of water has a mass of 1 kilogram
Note

Mass is different from weight. Mass stays the same regardless of location, while weight can change with gravity.

Metric mass units and their relationships

The metric system uses a base-10 structure, making conversions between units straightforward.

Key Relationships:
  • 1 kilogram (kg) = 1,000 grams (g)
  • 1 gram (g) = 1,000 milligrams (mg)
  • To convert from larger to smaller units, multiply
  • To convert from smaller to larger units, divide
Note

Remember that "kilo" means one thousand, so 1 kilogram equals 1,000 grams.

Converting between metric mass units

Converting between metric units involves moving the decimal point left or right based on the conversion factor.

Conversion Examples:
  • 3.5 kg = 3,500 g (move decimal 3 places right)
  • 750 g = 0.75 kg (move decimal 3 places left)
  • 2,400 mg = 2.4 g (move decimal 3 places left)
  • 0.08 kg = 80 g (move decimal 3 places right)
Note

When converting from kilograms to grams, you're multiplying by 1,000, so the number gets larger. When converting from grams to kilograms, you're dividing by 1,000, so the number gets smaller.

Comparing metric mass measurements

To compare measurements with different units, convert them to the same unit before making comparisons.

Comparison Examples:
  • Which is heavier: 0.4 kg or 450 g?
    0.4 kg = 400 g, so 450 g is heavier
  • Which is lighter: 2,500 mg or 3 g?
    2,500 mg = 2.5 g, so 2,500 mg is lighter
  • Order from lightest to heaviest: 0.7 kg, 650 g, 800,000 mg
    Convert all to grams: 700 g, 650 g, 800 g
    Order: 650 g, 700 g, 800 g
Note

Always double-check that you've converted all measurements to the same unit before comparing them.

Solving real world mass problems

Apply your knowledge of metric mass conversions to solve practical problems.

Real-World Scenarios:
  • A bag of apples weighs 2.3 kg. How many grams is this?
    2.3 kg × 1,000 = 2,300 g
  • A vitamin tablet contains 500 mg of calcium. How many grams is this?
    500 mg ÷ 1,000 = 0.5 g
  • If a box of cereal has a mass of 550 g, how many kilograms do 4 boxes weigh?
    550 g × 4 = 2,200 g = 2.2 kg
Note

When solving multi-step problems, write down each conversion to avoid errors.