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Fractions, Percentages and Expressing Risks

How to convert between percentages, decimals and fractions

Percentage to decimal
Decimal to percentage

5% to 0.05

  1. Simple swaps here.
  2. Remove the % at the end
  3. If <10 swap it for '0.0' at the start else swap it for '0.'

2.5% to 0.025

  1. Remove the % at the end
  2. If <10 swap it for '0.0' at the start else swap it for '0.'
  3. Drop the second decimal point

1/10 to 10%

  1. This is simpler.
  2. Multiply by 100 and add the % sign

1/25 to 4%

  1. Multiply by 100 (100 x 1/25 = 100/25)
  2. Add the % sign
Decimal to fraction
Fraction to decimal

0.025 to 25/1000

  1. Look for the right-most figure to find whether it’s tenths, hundredths or thousandths.
  2. Here 5 is in the 3rd column after the decimal point so we’ve got thousandths.
  3. 25 of them in fact.

0.1 to 1/10

  1. Here 1 is in the 1st column after the decimal point so we have tenths.
  2. Just one of them (1/10).

25/1000 to 0.025

  1. Divide the top (25) by the bottom (1000)
  2. Here dividing by 1000 is equivalent to moving the decimal point 3 places to the left.

1/10 to 0.1

  1. Divide the top (1) by the bottom (10)
  2. Here dividing by 10 is equivalent to moving the decimal point 1 place to the left.
Fraction to percentage
Percentage to fraction

1/10 to 10%

  1. This is simpler.
  2. Multiply by 100 and add the % sign

1/25 to 4%

  1. Multiply by 100 (100 x 1/25 = 100/25)
  2. Add the % sign

10% to 1/10

  1. Drop the % sign  (10)
  2. Divide by 100. (10/100)
  3. Rationalise (1/10)

4% to 1/25

  1. Drop the % sign  (4)
  2. Divide by 100. (4/100)
  3. Rationalise (1/25)

 Work it out

 

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