Page 130 - Start Up Mathematics_4
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The length from 0 to 1 is 1 cm, from 1 to 2 is 1 cm, and so on. This
                                       shows that there are 10 millimetres (mm) in 1 cm. Hence millimetre
             0                    1    is a smaller unit of measuring length.  10 mm = 1 cm


            Look at the following table to know the various units for measuring length.

                                                  (km)      kilometre
                                        × 10                                  1/10
                                                  (hm)      hectometre
                                        × 10      (dam)  decametre            1/10
                                        × 10      (m)         metre           1/10
                                        × 10      (dm)      decimetre         1/10

                                        × 10      (cm)      centimetre        1/10
                                        × 10                                  1/10
                                                  (mm)      millimetre


            To convert from a bigger unit to a smaller unit, multiply the value by 10 as many times till
            you reach that unit. For example, 1 km = (10 × 10) dam = 100 dam and 1 m = (10 × 10 ×
            10) mm = 1,000 mm.
                                                                                                    1
            Similarly, to change from a smaller unit to a bigger unit, multiply the value by            as many
                                                                      1     1      1             1   10
            times till you reach that unit. For example, 1 cm =          ×      ×     dam =          dam.
                                                                     10     10    10          1,000
            Example 1:      Fill in the blanks.
                            (a)  7 m = ____ cm                      (b)  6 cm = ____ mm

                            (c)  9 m 50 cm = ____ cm                (d)  2 cm 15 mm = ____ mm
                            (e)  70 mm = ____ cm

            Solution:                                                        Conversion Table
               (a)  1 m = 100 cm

                    So, 7 m = 7 × 100 cm = 700 cm.               1 km  =  10 hm            1 mm  =     1   cm
               (b)  1 cm = 10 mm                                                                      10
                    So, 6 cm = 6 × 10 mm = 60 mm.                1 hm  =  10 dam           1 cm  =     1   dm

                (c)   9 m 50 cm = 900 cm + 50 cm                                                      10
                                 = 950 cm                        1 dam  =  10 m            1 dm  =     1   m
                    So, 9 m 50 cm = 950 cm.                                                           10

               (d)  2 cm 15 mm = 20 mm + 15 mm                   1 m     =  10 dm          1 m     =   1   dam
                                   =  35 mm                                                           10

                    So, 2 cm 15 mm = 35 mm.                      1 dm  =  10 cm            1 dam  =    1   hm
                               1                                                                      10
               (e)  1 mm =        cm
                              10                                 1 cm  =  10 mm            1 hm  =     1   km
                                          1                                                           10
                    So, 70 mm = 70 ×         cm = 7 cm.
                                         10



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