Topic outline

    • Metric Measure of Length

      Measurement of something from its one end to the other is called its length. The standard unit of length is meter. We use different units to measure different lengths. Millimeter, centimeter , decimeter are smaller unit used to measure smaller distance, meter is used to measure average distance, whereas units like decameter, hectometer and kilometer are used to measure longer distance. All these units are related to each other.

       

      Changing Metric Units of Length


      When we move from one metric unit to another to the right in the above metric chart, the value of metric unit becomes ten times smaller i.e. one tenth and when we move from one metric unit to another to the left in the metric chart, the value of metric unit becomes ten times bigger.

      We consider meter as the basic unit of length.

      1 Decameter (dam) = 10 times meter

      1 Hectometer (hm) = 100 times meter

      1 Kilometer (km) = 1000 times meter

      1 Decimeter (dm) = 1/10 of meter

      1 centimeter (cm) = 1/100 of meter

      1 millimeter (mm) = 1/1000 of meter



      Conversion of measures from higher to lower units

      We always multiply when we change higher unit to lower unit.

      Example 1: Change 4km into meters

      1km =1000m

      Therefore, 4 x 1000m = 4000m

      Example 2: Change 25m into centimeters

      1m = 100cm

      Therefore, 25 x 100cm = 2500cm

       

      Conversion of measures from lower to higher units

      We always divide when we change lower unit to higher unit.

      Example 1: Change 6000m to kilometer

      1000m = 1km

      Therefore, 6000 ÷ 1000 = 6km

       

      Addition and Subtraction

      Step1: Write the units on the top.

      Step2: Write the numbers in proper place below the units. Write zero in empty place.

      Example 1: Add 45km 34m and 34km 5m 

      Example 2: Subtract 15km 30m from 35km 45m

             



      Multiplication involving units of measurement

      Example 1: Multiply 23 m 60cm by 5


       

      Division involving units of measurement

      Example 1: Divide 484m 60cm by 4           


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