High School Chemistry  ·  Practice by Skill

Significant Figures Practice Problems

Significant figures show how precise a measurement is, and they decide how many digits your final answer can honestly have. Every chemistry class uses them, so it pays to make the rules automatic. Here you can practice counting sig figs, rounding after a calculation, and writing numbers in scientific notation.

What you’ll practice

  • Counting sig figs: decide which digits in a measurement count, including tricky zeros.
  • Rounding after math: use the right rule for adding and subtracting versus multiplying and dividing.
  • Scientific notation: write very large and very small numbers in a form that keeps the sig figs clear.
  • Units and measurement: convert between SI units and read lab tools like a graduated cylinder.

Learn the method first →

A quick example: multiplying measurements

A rectangle measures 12.0 cm by 3.5 cm. What is its area?

Multiply: 12.0 × 3.5 = 42.0.

12.0 has 3 sig figs but 3.5 has only 2, and a product can only have as many sig figs as the least precise measurement.

Round to 2 sig figs: 42 cm2.

3 free significant figures problems

Give each one a real try before you open the solution. Your answer is checked as soon as you submit it, and the worked solution shows every step so you can see exactly where a setup went wrong.

#1Scientific Notation
Express 6,020,000 in scientific notation. (Enter your answer as: 6.02e6)
#2Chemistry Basics
Which question is most clearly a chemistry question?
#3Sig Figs — Addition
A student records two mass measurements: Mass1 = 25.38 g and Mass2 = 4.1 g. What is the total mass reported with the correct number of significant figures?

Questions you might have about significant figures

What are significant figures?
Significant figures are the digits in a measurement that carry real information: all the digits you were sure of, plus one estimated digit. They tell the reader how precise the measurement was.
How do I count significant figures?
Nonzero digits always count, and so do zeros between nonzero digits. Leading zeros never count. Trailing zeros count only when the number has a decimal point, so 0.00450 has 3 sig figs and 4500 has 2.
What is the sig fig rule for adding versus multiplying?
When you add or subtract, round to the fewest decimal places. When you multiply or divide, round to the fewest significant figures. Mixing those two rules up is one of the most common mistakes on tests.
How do I write a number in scientific notation?
Move the decimal point until you have a number between 1 and 10, then multiply by 10 raised to the number of places you moved it. Moving left gives a positive exponent and moving right gives a negative one, so 6,020,000 becomes 6.02 × 106.
High School Chemistry · Significant Figures Practice Problems