The relative decrease change. Definition:
The relative decrease change is the difference in an indicator over two periods in time, v1 - v2, relative to the value of the indicator in the earlier period, v1.
- Where:
- v1 - is called the reference value (original, initial number);
- v2 - is called the new value (the end value).
- In our case: v1 = 2,800, v2 = - 20.2.
The relative decrease change. Formula:
The relative decrease change =
The actual change / |v1|
(v1 - v2) / |v1| =
- Legend:
- v1 - the original number
- |v1| - the positive value of v1, |v1| >= 0. By example: |10| = 10; |-10| = 10.
- v2 - the new value
- The actual change = v1 - v2
- / - the fraction bar (division)
Why do we use |v1| in the formula instead of v1?
- Let's see what happens if we use v1 instead of |v1|:
- Choose a random negative number as the initial value: - 82.
- Choose a random positive number for the end value: 86.
Formula and calculation:
(v1 - v2) / v1 =
(- 82 - 86) / - 82 =
-168 / - 82 ≈
2.048780487805 ≈
2.05
Although the absolute difference is negative: -168, the relative decrease change is positive: 2.05. By using |v1| instead of v1, the error is corrected.
The relative percent decrease change. Detailed calculations below
By multiplying a number by the fraction 100/100,
we change only the form of the result, not the result.
- 100/100 = 100% = 100 ÷ 100 = 1.
- n × 100/100 = (n × 100)/100 = (n × 100)%, any number.
The relative percent decrease change. Formula:
The relative percent decrease change =
The relative decrease change × 100/100 =
(The relative decrease change × 100)/100 =
(The relative decrease change × 100)%
Calculate the relative percent decrease change:
(2,800 - (- 20.2))/|2,800| =
(2,800 + 20.2)/|2,800| =
2,820.2/2,800 =
2,820.2 ÷ 2,800 =
2,820.2 ÷ 2,800 × 100/100 =
(2,820.2 × 100 ÷ 2,800)/100 =
(282,020 ÷ 2,800)/100 ≈
100.721428571429/100 =
100.721428571429% ≈
100.72%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 2,800 to the final, end value - 20.2:
Rounded off to max. 12 decimal places ≈ 100.721428571429%
Rounded off to max. 2 decimal places ≈ 100.72%
The absolute (actual) difference
2,800 + 20.2 = 2,820.2
By what percentage has 2,800 decreased?
Answer: By ≈ 100.72%
By what percentage is - 20.2 smaller than 2,800?
Answer: By ≈ 100.72%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).