Each inch is divided into 16 lines, meaning that the space between each line is 1/16 inch long —this is the smallest length you can measure with a ruler. (Note that some rulers only go down to 1/8 inch lines, whereas others go down to 1/32 inch lines.) Next is 1/8 inch, which is the second-smallest unit of a ruler. The 1/8 lines are found midway between each 1/4-inch line: Example: Say you decide to measure the length of a corn on the cob. You find that your ruler comes to the second line after the 6-inch mark. This would mean that the corn is 6 1/8 inches long. The longest line represents the biggest unit on the ruler: 1 cm. Each centimeter is labeled on the ruler (1-30).

The Eye Level Reading Ruler is a coloured overlay filter and text highlighter about the size of an eight-inch ruler. It is discreet and professional-looking and can be kept in a book as a bookmark for easy storage. This Dyslexia Friendly resource helps relieve the symptoms of Visual Stress. Example: You take out a ruler to measure the width of your fingernail. The ruler stops at 1 cm, meaning that your nail is precisely 1 cm wide.Example: Say you’re measuring a piece of cloth and the ruler ends at the fourth line after the 10-inch mark. This would mean that the cloth is 10 1/4 (10.25) inches long. There have been huge advances in technology over the past decade, allowing for increasingly powerful assistive software to be created to help people overcome literacy difficulties. Sometimes however, the most effective tool that can be used is not complicated software, but instead something much simpler.

Inches correspond to the imperial system, which is the main measuring system used in the US and a smattering of other countries.

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If you counted in 1/8-inch increments, you'd find that the second line after 0 equals 1/8 inch, the fourth line 2/8 (1/4) inch, the sixth line 3/8 inch, the eighth line 4/8 (2/4 or 1/2) inch, the 10th line 5/8 inch, the 12th line 6/8 (3/4) inch, and the 14th line 7/8 inch. Like the inches ruler, you’ll see tons of lines on a metric ruler, with some longer and some shorter. Each line represents 1 millimeter, which is equal to 1/10 or 0.1 cm (so 10 mm make up 1 cm).

This is especially important to know if you’re studying science (recall that science generally uses the metric system —not the imperial system). Knowing how to read a ruler in cm is also helpful for people who'd prefer to not work with fractions (which you must do with inches) and who'd like to work with other units instead (in this case, millimeters). Also, be aware that 30 cm does not directly equal 12 inches, even though they are often put on the same ruler!

The second-biggest unit on a ruler is the 1/2 inch, which is represented by the second-longest line. These typically aren't labeled but might be on some rulers (in which case you'd see numbers such as 1 1/2 in, 2 1/2 in, etc.).