Hmmm ... now that was a bit different!  Let's have a look at this ...

1. We move the cursor to D4.6, so far so good.
2. Now we read our answer on the A scale.  Hello ... it's between two of the graduations!

Now this can happen quite often because we can't have marks for every number, so we need to estimate what this value is.  With a bit of practice, you'll become quite good at this.

On our slide rule, we see that the answer is a little bit more than 21, but less than 21.5; so I would say about 21.2 ... What do you think?

Now you may have thought 21.1 ... and that's not too bad either.

Okay, let's click here to go back to the lesson.