Students should be able to hold their hands a centimeter apart and a meter apart. This will help them in estimating linear distances. Students should also be able to pick up a paper clip and know it weighs about one gram. In the marble grab, students used their number sense to make a good estimate of the weight of the marbles. They knew that every five marbles weigh 26 grams and should reason that one marble would weigh a little more than 5 grams.
Students can use their number sense to make a good estimate.
When teaching young children to measure in standard units, it is important to have them examine the ruler to determine the endpoint of the measurement scale. The measurement scale on some rulers begins at the edge of the ruler while others have a definitive mark. Careful attention needs to be given to help young learners correctly position the ruler parallel to the line they are measuring.