Page 86 - classs 6 a_Neat
P. 86

DECIMALS IN EXPANDED FORM
        We read them as:
        point zero zero one, point zero zero two, . . . . . . , point zero zero nine, point zero one zero, point zero one one, .
        . . . . . , point zero nine nine, point one zero zero, point one zero one, . . . . . . , point nine nine nine respectively.   Place Value Table
        Remember that .001= 0.001, .011= 0.011, ... .                                                                                                                                                     Tenth     Hundredth    Thousandth
                                                                                                                                                 Thousands   Hundreds     Tens      Ones      Decimal      1           1             1
                                                                                                                                        72.63                                                  point
        EXAMPLES OF MIXED FRACTIONS AS DECIMALS                                                                                                    1,000       100         10         1          .         10         100          1000
                                                      1       17             29
        EXAMPLE 2:            Express the numbers 2       ,6       and 18          as decimals.                                        72.63                               7          2          .         6            3
                                                     10       100           1000
        Solution: We have:         1           1                                                                                     742.375                    7          4          2          .         3            7            5
                               2       = 2 +      = 2 + 0.1 = 2.1
                                  10          10
                                   17           17                                                                                                                        PRACTICE EXERCISE 6.1
                               6        = 6 +        = 6 + 0.17 = 6.17
                                  100          100

                                     29               29                                                                           1.  Write the following fractions in their decimal form.
                                18          = 18 +           = 18 + 0.029 = 18.029
                                    1000            1000                                                                                  (a)  6  (b)   9   (c)   52   (d)   57    (e)   245
                                                                                                                                              10       100       100        1000        1000
                                                        DECIMALS                                                                   2. Write the following in the decimal form.
                                                                                                                                          a.     Fifteen-hundredths
        DECIMALS The numbers expressed in decimal form are called decimal numbers or simply decimals.                                     b.     Seven-tenths
        EXAMPLE3:             Each of the numbers 5 .8, 19.63, 7.295, 0.068, etc., is a decimal.                                          c.     Forty-five-thousandths
                              A decimal has two parts, namely, (1) whole-number part and (ii) decimal part.                               d.     Eight and eight thousandth
                              These parts are separated by a dot(.), called the decimal point.                                            e.     Two hundred twenty-two and two hunderdth
                              The part on the left side of the decimal point ts the whole-number part and that on the
                              rightside of the decimal point ts the decimal part.                                                  3. Write the following in decimal form.


        EXAMPLE 4:            In 68.49, we have , whole-number part= 68 and decimal part= .49.                                            (a)  3  (b)   11  (c)  2036    (d)  14703    (e)  500005
                                                                                                                                              10       100         10          100            100
        DECIMAL PLACES The number of digits contained in the decimal part of a decimal gives the number of                         4.  Fill in the blanks.
        decimal places.
        EXAMPLE 5:            93 has two decimal places and 7.632 has three decimal places .                                              (a) 8.53 = 8 +  5   +   3   (b) 29.175 = 29 +   1  +   7    +   5   (c) 81.81 =  ‪  +  8   +   1

                                              Chart to Depict Decimal Fractions
                                                                             Decimal     Position of the Decimal                         (d) 66.666 =  ‪  +  6   +   6   +   6
                      Part                        Fraction
                                                                            Fraction              Point                            5.  Write in the expanded form
                                                  1       1                             1 place from the extreme                          a. 5.83       b. 62.37       C. 125.4      d. 12.543      e. 326.543
              One-tenth                               =                        0.1      right number
                                                  10      10

                                                1          1                            2 places from the extreme                  6.     Write in the short form.
              One-hundredth                         =                          0.01     right number.
                                              100       10 × 10                                                                           a. 0.8 + 0.08 + 0.008

                                             1            1                             3 places from the                                 b. 3 + 0.1 + 0.02 + 0.003
              One-thousandth                      =                           0.001     extreme right number.                             c. 51 + 0.02 + 0.003
                                           1,000     10 × 10 ×10                                                                          d. 100 + 10 + 1 + 0.1 + 0.01 + 0.001

                                           1                1                           4 places from the                                 e. 900 + 80 + 9 + 0.5 + 0.009
              One-ten thousandth                =                             0.0001    extreme right number:
                                        10,000      10 × 10 × 10 × 10

              One-hundred                1     =             1                          5 places from the
              thousandth             1,00,000     10 × 10 × 10 × 10 × 10     0.00001    extreme right number
   81   82   83   84   85   86   87   88   89   90   91