Logarithms and calculators

Base 10 logs

log 2 = .301

log 3 = .477

log 5 = .699

log 7 = .845

How to remember these

log 2 = 2 * .15

log 3 = 3 * .16

log 5 = 5 * .14

log 7 = 7 * .12

So it starts at .15, goes up to .16, down to .15 at log 4 and .14 at log 5 and .13 at log 6 and .12 at log 7.

These are approximations. Using a calculator like Google can check how accurate they are.

Just remember .16 for 3. Then count down by .01 in either direction per whole number. This approximately works up to 10. You can straight line interpolate between whole numbers using the same slope. You can then work on improvements to this rule.

http://www.karlscalculus.org/l6_3-2.html

http://oldmathdognewtricks.blogspot.com/2012/05/my-version-of-log-wars.html

About these ads

About New Math Done Right

Author of Pre-Algebra New Math Done Right Peano Axioms. A below college level self study book on the Peano Axioms and proofs of the associative and commutative laws of addition. President of Mathematical Finance Company. Provides economic scenario generators to financial institutions.
This entry was posted in Constructing Logarithm Tables, Logarithms. Bookmark the permalink.

2 Responses to Logarithms and calculators

  1. friv 7 says:

    The logical relationship to each other, but also not too hard to remember.

  2. juegos Friv says:

    I like the helpful info you provide in your articles.
    I will bookmark your weblog and check again here regularly.
    I’m quite sure I’ll learn many new stuff right here!
    Best of luck for the next!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s