How to decrease the number - 20
by - 6.4% of its value?
Value of Percentage Decrease. New Value
- A percentage value is nothing but a fraction with a denominator of 100:
- - 6.4% = - 6.4/100 = - 6.4 ÷ 100 = - 0.064
- ...
- To decrease a negative number, don't subtract from it, but add to it the 'Value of Percentage Decrease'.
- To decrease a positive number, subtract from it the 'Value of Percentage Decrease'.
- ...
Value of Percentage Decrease =
Percentage of the Decrease % × The original value =
- 6.4% × - 20
New Value =
The original value - Value of Percentage Decrease =
- 20 + (- 6.4% × - 20)
1. Calculate the End Value
decreased by a percentage of its Initial Value
End Value =
- 20 + Value of Percentage Decrease =
- 20 + (- 6.4% × - 20) =
- 20 - 6.4% × - 20 =
(- 20 is a common factor)
(1 - 6.4%) × - 20 =
(100% - 6.4%) × - 20 =
93.6% × - 20 =
93.6 ÷ 100 × - 20 =
93.6 × - 20 ÷ 100 =
- 1,872 ÷ 100 =
- 18.72
2. Value of Percentage Decrease
It can be calculated in two ways.
The first method:
Value of Percentage Decrease =
Percentage of the Decrease % × The original value =
- 6.4% × - 20
The second method:
Value of Percentage Decrease =
The original value - New Value
Value of Percentage Decrease =
- 1.28
The value of the decrease is negative, so we are actually dealing with a Percentage Increase.
The end value: - 20 decreased by - 6.4% percent = - 18.72
Value of Percentage Decrease = - 1.28