While it may seem to be a very basic skill, being able to read a ruler is the foundation to just about any project you make by hand or even with a Shopbot!  Reading a metric ruler is pretty simple- no fractions, everything converts nicely in factors of 10, and its pretty straight forward.  The English system, however, can be kind of confusing- fractions, units, and symbols.  This instructable will help you understand how to use a "standard" ruler better; specifically being able to read fractions of an inch or "Drawing the Inch" as I call it with my students.

The cool thing about knowing how to label the fractions inside of an inch is that you can use it as a calculator to reduce fractions!  Follow along and I'll show you how.  This instructable may be a little hard to follow if you don't read it through all the way to the end before trying it out.

Step 1: Start your Inches!

Gather supplies.  See Picture 1. You need:

Pencil or Pen

That's it!

A few definitions that might help you understand this instructable a little better:

Numerator:  The number above the line in a common fraction
Denominator:  The number below the line in a common fraction

The easiest way I have found to explain an inch is to draw it out, starting with a mark representing zero and a mark representing 1.  These DO NOT HAVE TO BE ACCURATE!!!  I find it is a lot easier if you make your "inch" BIG to give you more room to write in the fractions.  SO:

On the paper, Draw a rectangle as shown in Picture 2 and 3.  This is going to be our "ruler".  Remember to make it big!  On the ruler, make a mark, also as shown in Pictures 2, 3, and 4.  This will be out 1 inch mark.
<p>Fantastic! </p><p>Here's my little piece of the world...</p><p>http://www.craft-a-project.com/Ruler-Measurements.html</p>
<p>Wow! How cool is this. Every everybody should know this little trick. This has taught me how to read a ruler and I do not think I will forget it. Thank you soooo much for sharing this.</p>
<p>Thanks! Glad it could help. I've wondered who views this instructable- There are hardly any comments yet it has over 100k views. Would love to hear how (if?) others are using this in some way? </p>
A nice instructable! Some times one needs to discuss the obvious. I am a physicist, I live in a metric world and during my education I had to use the log rule a lot. The way I see it the metric system is more &quot;flat&quot; since 0.7 has no qualitative difference than 0.8 and it is easier to think of the increase, on the other hand when you jump from 1/4 to 3/8 you have to re-adjust your mind in dividing the pie in 8 instead of 4 pieces. Not to mention that if you ask me where the 13/16 is on the ruler I'll have to think a little.
This is a great way to explain and use fractional measurements in any project, or to learn and practice fractions for any other purpose. Kudos for your teaching method! (I agree, metric is a LOT easier, but sometimes you just have to work with what you've got.) Next, maybe somebody can show how to use those 3-sided architectural scale rulers ...
..Still don't get the reason why one should choose to hurt himself so much...<br><br>Why not simply jump to the metric ???
I agree... The metric system is just so much easier. Unfortunately, my students still need to know BOTH systems. Guess which one they struggle with more? I will say this though, my students understand their fractions a lot better after learning their inch.

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