Core Focus on Decimals & Fractions Measuring in Inches Lesson 3.7

Warm-up 1.What units are used in the United States to measure length or distance? 2.Which is larger, ? 3.Which is larger, ? 4.Simplify the fraction. 5.Simplify the fraction. inches, feet, miles

Measuring in Inches Use a customary ruler to measure inches and fractions of an inch. Lesson 3.7

Good to Know! In many careers it is important to know how to measure accurately using a ruler. A ruler measures inches using different sized denominators. A foot-long ruler has 12 inches. Each inch is separated into sixteenths ( ) on the ruler using different sized lines, called tick marks. There are sixteen equally divided spaces between every inch on a ruler.

Step 1Copy and complete the table below by writing each fraction in simplest form. Step 2How many fractions in the table above simplify to a whole number? What do you notice about the tick mark(s) on the ruler that correspond to the measurement(s) that are whole numbers? Step 3After simplifying the fractions, how many fractions have a 2 in the denominator? What do you notice about the tick marks on the ruler that correspond to the measurements with a 2 in the denominator? Step 4How many of the simplified fractions have a 4 in the denominator? What do you notice about the tick marks on the ruler that correspond to the measurements with a 4 in the denominator? Step 5How many fractions have an 8 in the denominator? What do you notice about the tick marks on the ruler that correspond to the measurements with an 8 in the denominator? Step 6After simplifying the fractions, how many fractions have a 16 in the denominator? What do you notice about the tick marks on the ruler that correspond to the measurements with a 16 in the denominator?

Measuring with a Customary Ruler 1.Locate the tick mark that most closely matches the length of the object. 2.Record the whole number of inches. 3.Record the fractional part of an inch that the tick mark represents. 4.Write the whole number of inches with the fraction part of an inch in simplest form.

Example 1 Measure the line using inches on a ruler. Measure to the nearest 16 th of an inch. a. Line up the “0” inch mark of the ruler with the left edge of the line drawn. Identify which mark on the ruler corresponds to the right end of the line. The line corresponds to 3 whole inches plus 2 additional tick marks. Write the fraction in simplest form.

Example 1 Continued… Measure the line using inches on a ruler. Measure to the nearest 16 th of an inch. b. Line up the “0” inch mark of the ruler with the left edge of the line drawn. Identify which mark on the ruler corresponds to the right end of the line. The line corresponds to 2 whole inches plus 4 additional tick marks. Write the fraction in simplest form.

Example 2 Measure the line to the nearest quarter inch. Measuring to the nearest quarter inch means the answer could include Use a ruler to see that the line is 2 inches and then ends closer to the tick mark than the tick mark. The line is about inches long. Notice: and

Communication Prompt What is the most difficult aspect of using inches for measurements?

Exit Problems 1.Draw and label a line that is inches long. 2.Draw and label a line that is inches long. 3.Draw and label a line that is inches long. 4.Measure ___________ to the nearest sixteenth of an inch (fill in the blank with an item you have with you).