Power rule of logarithms worksheets

A number in front of a logarithm can go up as a power. These free printable worksheets practice that one law on its own, turning 3 log₂ 3 into log₂ 27 and 2 log 12 into log 144.

Power rule of logarithms
Power rule of logarithms worksheet — Bases 2–10, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

The move is short, and the mistake is multiplying where the power belongs. 3 log₂ 3 is log₂ 27, because 3³ is 27, and a student who multiplies gets log₂ 9. The reason is the same as the rest of this family: a logarithm is an exponent, and multiplying an exponent raises the power.

Why this sheet works

This law is the one that matters most later on. It is how an unknown exponent gets brought down so an exponential equation can be solved, and that step only feels natural to a student who has already moved numbers in this direction. Here they go up; in that equation they come down.

How this one works

3 log₁₀ 3

3 log₁₀ 3
k log₁₀ m = log₁₀ (mᵏ)
3³ = 27
3 log₁₀ 3=log₁₀ 27
  1. Both logarithms are to the same base, 10. Only logs with the same base can be combined.
  2. A number in front of a log moves up to become a power of what is inside.
  3. So the two arguments become one: 3³ = 27. The answer is log₁₀ 27.