To assess students' prior knowledge, invite them to reflect on the previous lesson. Ask them to describe what they learned that make fractions easier to understand and use.
To begin the lesson, give students an inch ruler and the
Inch by Inch Activity Sheet. Tell them that today they will use a standard inch ruler to measure lengths.
Ask students how long their ruler is in inches. Remind them that a ruler is usually 12 inches long. Tell students that a long time ago, people used to measure things with their fingers, hands, and feet. The only problem was that every finger, hand, and foot was not the same length. This caused problems when trying to measure accurately.
Today, we know that the standard unit, "one foot," is equivalent to 12 inches. Using standard units like the foot or the inch helps people measure accurately.
Tell students that when they measure using an inch ruler, each inch ends at the long line above the number and that each inch is further divided into smaller parts. They can represent these parts using fractions.
The half-inch (1/2 inch) mark is exactly halfway between each number. Half-inch (1/2 inch) marks are the next longest lines. The quarter-inch (1/4 inch) marks show 1/4 of an inch and 3/4 of an inch. These markings are slightly shorter than the 1/2 inch markings. The ruler also includes smaller divisions.
Have students determine the fractional part for each of the small markings. Students should discover that each inch is further divided into 16 smaller sections. Remind students that when they measure, they always begin measuring from the left end of the ruler.
Have students use the
Inch by Inch Activity Sheet to practice measuring various lengths. Assign each student a partner. Go over a few examples as a class to ensure that students are reading the ruler accurately, and then allow them to complete the remainder of the Student Learning Guide independently.
As students complete the exercise, ask them to compare their responses to their partner’s responses. If their answers differ, students should continue to work on the items until they have reached agreement. Once everyone has reached agreement, go over the answers as a class.
Next, have pairs work together to measure the items on Part II of the
Inch by Inch Activity Sheet. Students should estimate the length in inches before actually measuring.
As pairs complete the actual measurements, ask them to compare their responses to another pair’s responses. If their answers differ, students should remeasure and continue to work on the items until they have reached agreement. Once everyone has reached agreement, discuss measurements as a class.
