Mass is how heavy something is. We measure it in grams (g) and kilograms (kg). A paper clip has a mass of about 1 g and a big bag of flour about 1 kg, which is 1000 g.
Liquid volume is how much liquid a container holds. We measure it in liters (L) and milliliters (mL). You can add, subtract, multiply and divide masses and volumes just like other numbers, as long as the units match.
Worked example
A bag of rice is 450 g. A bag of pasta is 375 g. What is their total mass?
- Both are in grams, so add them.
- 450 + 375 = 825.
Answer:825 g
Key words
- mass
- how heavy something is
- gram (g)
- a small unit of mass
- liter (L)
- a unit of liquid volume
Practise this
New questions every time.
Common Core-referenced: 3.MD.A.2