Make copies of worksheets that children can use to practice measuring with a ruler. Worksheets can have images of different objects used in school, such as a pen, pencil, crayon, paint brush, paper clip, glue stick eraser and scissors. Kids use a ruler to measure each of the images and record their findings. Another worksheet can have numbers in 1/2-inch increments with some spaces left blank so kids can fill in the proper measurement. Kids can work on this activity to practice counting halves by reading a ruler.
Likewise, kids can be given different objects to measure instead of using an activity sheet. Kids can measure and record the lengths of the same school supplies as those on the activity sheet as well as a wide range of other objects. For example, children can measure a chair's leg, the width of a desk, a blackboard, shoe, book, box of crayons, calculator or their locker. Take the kids outdoors to measure and record the length of twigs, leaves and flower stems.
Divide children into groups or pairs so they can work together to learn how to measure. Give each group or pair pieces of yarn cut into different lengths. The kids can work together to hold out the yarn while one person measures how long each strand of yarn is using a ruler. In another activity, kids can work together by using a ruler to measure their height. The kids can even lay flat on a large piece or paper while their partner uses a pencil or marker to outline their shape. Kids can indicate their height at the top of their head after they are measured and design the image to make it look like them.
Dozens, if not hundreds of websites have online activities and games that kids can work on to learn how to measure. BBC's "Skillswise Measuring," for example, teaches kids about length, weight and capacity through games, worksheets and quizzes. AAA Math has online lessons and exercises on metric prefixes, symbols, number values and length, and Fun Brain's "Measure It!" is a multiple choice game where kids can practice measuring lines with either centimeters or inches in easy, medium or hard skill levels.