Many children and adults have significant
difficulty reading a ruler.
Those who have visual perception problems
many not be able to distinguish the different
lengths of the lines between inch marks.
For some the cause of their poor ruler
reading skill is not understanding fractions;
for others the cause is the layout of the ruler
1. contains a picture of a typical ruler.
Notice that the numbers for the inch
marks are located next to the inch mark rather
than directly under the inch mark.
For individuals who do not know how to
read a ruler this is confusing. These people think that the number is the location of the
inch mark rather than the line next to it.
Individuals who do not understand
fractions are confused by the concept of
quarters and eights.
A person might read ¼ , ½ and ¼
instead of ¼, ½, and ¾ .
If a person has difficulty understanding
quarters then eights and sixteenths are
Figure 2. shows a ruler designed to help
teach the concepts of quarters.
For individuals who have no problems
reading rulers these problems are difficult to
To assist individuals who have had difficulty
learning to measure, have the person start to
measure things in the room by rounding to the
nearest inch. A tabletop that is 24 and ¾ inches would be rounded to 25
bottle cap that measures 7/8 would be rounded to
1 inch. A
cup that measures 3 and ¼ inches would be
rounded to 3 inches. This will allow the person to become familiar with measuring
and the numbers associated with the things
around them without worrying about the
fractions. As noted above, not understanding the
fractions is often the reason the person did not
learn to measure with a ruler in the first
After the person can measure easily to
the nearest inch, he or she can be taught to
round to the nearest half inch.
This ruler has the half-inch clearly
marked making it easier for the person to learn
how to measure to the nearest half inch.
The next step is to have the person
measure to the nearest quarter inch.
This ruler is ideal for learning this
step since the quarters are marked.
Once the person has mastered rounding to
the nearest ¼, ½, or ¾, the student can be
taught to read eights.
It may take longer for the person to
master measuring to the nearest eighth but with
sufficient practice most individuals can learn
If the student has great difficulty with
measuring to the nearest eighth, the students
vision should be checked.