No need to hide like the turtle. Fractions can be conquered. Pass the mouse over the unsure turtle and see how he comes out of his shell to learn more about fractions.

Fractions are encountered just about every time you step into the shop. Here is a link to some pages that go over the basics of fraction math. It is from S.O.S Math web site, which is a free resource of math review material. You will find a topic such as fractions broken down into logical sections with very good explanations and problems to check your understanding.

What follows are a few tools to make working with fractions easier in your shop.

First, are two tables you can print out to keep in your shop. They show addition and subtraction for the most common fractions used by woodworkers. From 1/2 to n/16 each table has all combinations of addition or substraction. To use the table for addition, pick your first fraction from the top row, find the second fraction in the first column then read across until the column and row intersect (see red line on table for this example). Follow same process for subtraction using the subtraction table. For example; 3/4 - 3/8 is computed by finding 3/4 in the top row and 3/8 in the left column. Read the answer on the intersection. (see blue line on the table).

You can also download PDF files for each table.

For example: 3/4 + 3/8 = 1 1/8 and 3/4 - 3/8 = 3/8

Second, I have included a diagram of an easy to make shop calculator to add and subtract fractions.

Third, you can see an easy to make non-electronic calculator for addition and substraction of fractions. The calculator is a form of a nomograph. It is made by using two regular rulers one above another. To add two fractions, slide the top ruler until its left edge lines up with the first number. In the picture below the first number is 3/8. Find the second number on the top ruler, say 5/16, then read the sum on the ruler below. The picture shows two examples: 3/8 + 5/16 = 1 11/16; and 3/8 + 7/8 = 1 1/4

To sutract two fractions, find the first fraction on the bottom ruler. Move the top ruler until the second fraction is directly above the first. On the picture look at 1 1/4 on the bottom (yellow ruler) , above it (on the aqua ruler) you will find 7/8. Now go the the left end of the top rule and read the answer on the bottom ruler. 1 1/4 - 7/8 = 3/8.

Fractions Plus Table (click for pdf)

Fractions Minus Table (click for pdf)

Fractions Calculator