1. Estimating and Measuring Lengths in Meters and Centimeters 3B: 6.1a

2. Words to Know  Meter  Centimeter  Convert

3. Activity Time  We’re going to find out the length of several items in the classroom.  Let’s start with the height of the board. How high do you think it is?  Write your estimate on your paper in the 1 st column.  Now estimate the length/height of the first 5 items on your paper.

4. Time to measure…  Now let’s use the meter sticks to measure them.  Write the length to the nearest meter under the “Measurement 1” heading.  Was it hard to estimate the height or length of the items?  Do you have a way to estimate?  The meter stick doesn’t show the exact length, so use the word ‘about’ to describe the length and round to the nearest meter.

5. Accuracy  To measure more accurately we need a measurement smaller than a meter.  What measurement might we use?  Centimeters  Look at your ruler or meter stick.  You should see 10 small markings followed by the digit ‘1’. This is a centimeter.

6. More estimates and measurements  Using centimeters, estimate the length of your thumb. Record this on your paper.  Try to estimate the width of your palm.  Now measure ALL the items on your list, using meters and centimeters. Record your results in the last column.

7. Meters or Centimeters?  Hold up a c or an m to tell what unit we should use to measure the following…  The length of your pencil  The length of the classroom  The height of a flag pole  The distance from your elbow to the tip of your fingers

8. Conversions  Look at your meter stick.  How many centimeters make a meter?  Let’s start a conversion poster.  100cm = 1m  How many centimeters make 2 meters?  2m = _____ cm  2m = 2 x 100cm = 200cm

9. More conversions  Try these in your notebook… 4m =4 x 100 cm= 400cm 7m =7 x 100 cm= 700cm 9m =9 x 100 cm= 900cm 10m =10 x 100 cm= 1000cm 30m =30 x 100cm= 3000cm

10. Conversions  How many centimeters is 3 m 28 cm?  First convert the meters.  You still have another 28 cm.  3 m 28 cm = ________cm  3 m = 300 cm  300 + 28 = 328 cm

11. More conversions  How many centimeters is 4 m 8 cm?  4 m = 400 cm  400 + 8 = 308 cm  Now you try one more…  How many centimeters is 2 m 12 cm?  200 + 12 = 212 cm

12. Conversions, continued  How many meters and centimeters make up 643 cm?  How many 100 cm can be taken from 643 cm?  600 cm is 6 m. There are 43 cm left.  643 cm = ______m______cm 643 cm 600 cm 43 cm 643

13. Conversions, continued  How many meters and centimeters make up 904 cm?  How many 100 cm can be taken from 904 cm?  900 cm is 9 m. There are 4 cm left.  904 cm = ______m______cm 904 cm 900 cm 4 cm 94

14. Your turn  Go to Textbook page 9-10 and do tasks 1- 4 and 6-10.  Work together to do page 9, task 5  Homework: WB exercise 1, pg. 7