Notes on Decimal | Grade 7 > Compulsory Maths > Fractions and Decimals | KULLABS.COM

Decimal

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Decimal

The denominators of the fractions which have the power of 10 then such fractions are called decimal fractions. For example,

Source :worldartsme.com Fig :Decimal
Source :worldartsme.com
Fig :Decimal

\(\frac{8}{10}\) = 0.8

\(\frac{13}{100}\) = 0.13

Terminating and Non-Terminating recurring decimal

When a fraction is expressed in decimal and the decimal part is terminated with a certain number of digits, it is called terminating decimal.

\(\frac{1}{3}\) = 0.3333....

\(\frac{1}{6}\) = 0.16666......

\(\frac{8}{7}\) = 1.1428571....

Similarly, when the fraction is expressed in decimal and the decimal part is never terminated it is called non-terminating decimal. For example,

\(\frac{2}{3}\) = 0.666....

\(\frac{7}{9}\) = 0.7777...

\(\frac{6}{7}\) = 0.857114285......

Four Fundamental operations on decimals

  1. Addition and Subtraction of decimals
    While adding and subtracting decimals, we should arrange them in such a way that the digits at the same places should lie in the same
    Souce :student.passassured.com Fig :Calculations, Fractions, Decimals
    Souce :student.passassured.com
    Fig :Calculations, Fractions, Decimals
    column.
    Add: 2.5
    +9.08
    \(\overline{11.58}\)
    Subtract: 18.79
    - 7.843
    \(\overline{10.947}\)
  2. Multiplication of decimals
    In the case of multiplying a decimal number by 10 or the power of 10. We should simplify shift the decimal point to the right of as many numbers of digits as there are number of zeros in 10, 100, 1000, etc, For example:
    Multiply8.367 by 10
    8.367× 10 = 83.67
  3. Division of decimals
    To divide a decimal by another decimal, we should first eliminate the decimal point from the divisor multiplying it by some power of 10. In the same time, the dividend should also be multiplied by the same power of 10. Then we should proceed the division.
    Divide 74 by 10
    \(\frac{74}{10}\) = 7.4



  • Four Fundamental operations on decimals

    1. Addition and Subtraction of decimals
    2. Multiplication of decimals
    3. Division of decimals
.

Very Short Questions

Solution : 

2\(\frac{3}{4}\) + 1\(\frac{5}{8}\) -3\(\frac{1}{3}\)

= \(\frac{11}{4}\) + \(\frac{13}{8}\) -\(\frac{10}{3}\)

=\(\frac{11x6+13x3-10x8}{24}\)

=\(\frac{66+39-80}{24}\)

=\(\frac{105-80}{24}\)

=\(\frac{25}{24}\)

=1\(\frac{1}{24}\)

 

 

 

0%
  • Express the 0.3 decimals in fractions.

    (frac{3}{2})
    (frac{1}{2})
    (frac{2}{3})
    (frac{1}{3})
  • Add : 
    0.236 + 0.579

    0.733
    0.815
    0.934
    0.672
  • Subtract:
    0.9 - 0.45

    0.-36
    0.9
    0.45
    0.36
  • Simplify:
    18.8 - 6.23 + 5.94

    18.62
    18.115
    18.443
    18.51
  • Express (frac{3}{5}) fraction into decimal.

    0.6
    0.4
    0.3
    0.5
  • Express the 0.3 decimal into fractions.

    (frac{2}{3}) 
    (frac{3}{2}) 
    (frac{1}{3}) 
    1
  • Add:
    0.236 + 0.579 

    0.678
    0.815 
    0.343
    0.235
  • Subtract: 
    24.3 - 15.072

    9.288
    10.01
    8.235
    7.352
  • Simplify: 
    18.8 - 6.23 + 5.94

    19.23
    18.51
    20.65
    17.45
  • Multiply: 
    7.68 by 8

    61.44
    61.54
    58.32
    59..43
  • You scored /10


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