Core Focus on Decimals & Fractions Lesson 1.3 Core Focus on Decimals & Fractions Measuring in Centimeters

Warm-Up (page 11) 1. Which is larger, 5.4 or 5.7? 2. Which is smaller, 4.8 or 4.3? 3. Write the decimal that represents the following words: eight and five tenths. 4. Write the decimal that represents the following words: eleven and four tenths. Please write in the Time Tracker: Centimeters, Page 13.

Measuring in Centimeters Lesson 1.3 Measuring in Centimeters I can measure and draw line segments using centimeters.

Vocabulary Metric System A decimal system of measurement.  The metric system is used in a majority of countries around the world.  The basic unit of length in the metric system is the meter. Other metric units, such as millimeters, centimeters, and kilometers, are based on the meter.

Vocabulary Continued… Tick Marks The metric ruler is divided up using tick marks. Tick marks are equally divided spaces marked with a small line.  Each whole number on a metric ruler represents a centimeter (cm).  The small tick marks between each centimeter represent millimeters (mm).  There are 10 millimeters in 1 centimeter. One millimeter is one-tenth of a centimeter. cm 1 cm 6 and cm = 6.3 cm

Example 1 Find the length of the line to the nearest tenth of a centimeter. Line up the 0 mark on the ruler with the left edge of the line. Identify the tick mark that represents the length of the line. Each small tick mark represents 0.1 centimeters. Count the number of tick marks after the last whole number to find the number of tenths. 6 + 0.3 = 6.3 cm WHOLE NUMBER + TENTHS = TOTAL LENGTH The length of the line is 6.3 cm.

8.8 is closer to 9.0 centimeters than 8.5 Example 2 Find the length of the line to the nearest half centimeter. Line up the 0 mark on the ruler with the left edge of the line. Identify the tick mark that represents the length of the line. The line is approximately 9 centimeters long. 8.8 is closer to 9.0 centimeters than 8.5 8.8

Communication Prompt How is measuring with centimeters related to decimals?

Practice ISN page 13

Exit Problems Answers Vary 1. Draw and label a line that is 2.4 cm long. 2. Draw and label a line that is 9.9 cm long. 3. Draw and label a line that is 7.5 cm long. 4. Measure ___________ to the nearest centimeter (fill in the blank with an item you have with you). Answers Vary