Being able to measure using a ruler is an essential skill your child will be expected to learn in school. You can begin teaching measurement even to very young children through games. Encourage a young child to use non-standard measurements, such as “two hands high.” Preschoolers can use their fingers, hands or feet as a simple way to measure. When she's ready, start with a simplified ruler printed with large numbers to introduce your child to measurements.
Let your child examine a ruler. Explain that the numbers allow her to measure and compare the size of things. Discuss the ways measurement is used in everyday life.
Introduce the concept of an inch to older preschoolers and young school-age children. Point out to your child that each number on the ruler equals 1 inch. Let her use the ruler to measure toys and her own fingers and toes.
Explain that the ruler is read from left to right, just like the words on a page. Show your child how to line up the ruler starting with the “0” on the left side when measuring. Explain that some rulers do not print the “0” and instead begin with “1.”
Introduce the smaller markings on the ruler as your child becomes adept at measuring inches. Begin with the half-inch markings, which are the second-longest lines on the ruler after inches.
Introduce quarter-inches next, then eighths and sixteenths as your child is able. Point out that the lines indicating quarter-inches are shorter than those for half-inches, while eighths and sixteenths are shorter yet.
Let your child play online games that reinforce her ruler-reading skills.
Have your child estimate the length or height of items around the house, then measure them with a ruler. This will give her experience judging size and give her practice using the ruler.
Provide your child with opportunities to use other measuring tools besides a ruler, for example, a yard stick, a retractable metal measuring tape and a soft dressmaker’s tape.
Have your child apply her skills using the ruler in a craft project you work on together, suggests the Teach Kids How website. Sewing, woodworking, gardening and scrapbooking are among the many activities which require measuring.