Page 88 - classs 6 a_Neat
P. 88

7. Complete the given sequences by writing the next three decimal numbers.                                                                                            SOME EXAMPLES


               a.      2.1,2.2,2.3, _________                                                                                      EXAMPLE 4:           Convert 5.3, 7.19, 0.376 and 84 into like decimals.
               b.      7.123, 7.124, 7.125, _________
               c.      15.8, 15.9, 16.0, _________                                                                                 SOLUTION:  In the given numbers, the maximum number of decimal places is 3. So, we convert each one of
               d.      20.01, 20.02, 20.03, ________                                                                               the given numbers into one having 3 decimal places by annexing suitable number of zeros to the extreme right
               e.      152.1, 152.2, 152.3, _________                                                                              of the decimal part.
                                                                                                                                                        5.3 = 5.300, 7.19 = 7.190, 0.376 = 0.376 and 84 = 84.000.
        8. Write three equivalent decimals for each of the following.                                                                                   Thus, 5.300, 7. 190, 0.376 and 84.000 are the required like decimals.
               a.0.5          b.3.6         c.20.7         d.62.35              e.146.9
                                                                                                                                   EXAMPLE 5:           Arrange the digits of 269.374 in the place-value chart. Write the place value of each
        9.Write each of the following fractions as decimals by converting the denominators into multiples of 10.                                        digit.   Also, write 269.374 in expanded form.
                    1       3       17        4         29                                                                         SOLUTION:            We may arrange the digits of the given number in the place-value chart as shown
               (a)     (b)     (c)       (d)       (e)                                                                                                   below.
                    2       5       20        25        500

        10. Use a graph paper to illustrate the following decimal fractions.                                                            Hundreds         Tens          Ones         Decimal        Tenths     Hundredths     Thousandths
                                                                                                                                                                                     point
                     7        3        21         47          3
               (a)       (b)      (c)       (d)        (e)                                                                                   2             6             9              .             3             7              4
                    10       10       100        100        100
                                           LIKE AND UNLIKE DECIMALS


        LIKE DECIMALS Decimals having the same number of decimal places are called like decimals.                                   In 269.374, we have:

        EXAMPLE 1:             9.82, 6.03, 14.58 are like decimals, each having two decimal places.                                       Place value of 2 = 2 hundreds = 200.
                                                                                                                                          Place value of 6 = 6 tens = 60.
        UNLIKE DECIMALS Decimals having dl[ferent number of decimal places are called unlike                                              place value of 9 = 9 ones = 9
               decimals.                                                                                                                                                3
                                                                                                                                          place value of  3 = 3 tenths =   .
                                                                                                                                                                       10
        EXAMPLE 2:            Clearly, 6.4, 8.93, 12.065 are unlike decimals.
                                                                                                                                          Place value of  7 = 7 hundredths =  7   .
        AN IMPORTANT RESULT                                                                                                                                                 100
                              We shall show that 0.6 = 0.60 = 0.600, etc.                                                                                                     4
                                       6         6 × 10        60                                                                         Place value of 4 = 4 thousandths =   1000  .
                               0.6 =        =              =        = 0.60
                                       10       10 × 10        100                                                                        269.374 = 2 hundreds+ 6 tens+ 9 ones+ 3 tenths+ 7 hundredths. + 4 thousandths
                                       6         6 × 100        600
                               0.6 =        =               =         = 0.600                                                                                3        7          4
                                       10        10 × 100       1000                                                                       = 200 + 60 + 9 +       +        +
                              0.6 = 0.60 = 0.600 etc.                                                                                                        10      100       1000
                                                                                                                                          COMPARING DECIMALS
        RESULT  Putting any number of zeros to the extreme right of the decimal part of a decimal does not                                Suppose we have to compare two decimals. Then, we proceed according to the following steps.
                       change its value.                                                                                                  Step 1. Convert the given decimals into like decimals.
                                                                                                                                          Step 2. First compare the whole-number part.

        Thus, we may write 2.64 = 2.640 = 2.6400, etc.                                                                                    The decimal with the greater whole-number part is greater.
        Thus, we may convert unlike decimals into like decimals by annexing the required number of zeros to the
        extreme right of the decimal part.                                                                                         Step 3.  If the whole-number parts are equal, compare the tenths digits.
                                                                                                                                           The decimal with the bigger digit in the tenths place is greater.
                                                                                                                                   Step 4. If the tenths digits are also equal, compare the hundredths digits, and so on. The following examples
                                                                                                                                          will make the ideas more clear.
   83   84   85   86   87   88   89   90   91   92   93