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 = 136, v2 = 84.7.
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: - 43.
- Choose a random positive number for the end value: 59.
Formula and calculation:
(v1 - v2) / v1 =
(- 43 - 59) / - 43 =
-102 / - 43 ≈
2.372093023256 ≈
2.37
Although the absolute difference is negative: -102, the relative decrease change is positive: 2.37. 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:
(136 - 84.7)/|136| =
51.3/136 =
51.3 ÷ 136 =
51.3 ÷ 136 × 100/100 =
(51.3 × 100 ÷ 136)/100 =
(5,130 ÷ 136)/100 ≈
37.720588235294/100 =
37.720588235294% ≈
37.72%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 136 to the final, end value 84.7:
Rounded off to max. 12 decimal places ≈ 37.720588235294%
Rounded off to max. 2 decimal places ≈ 37.72%
The absolute (actual) difference
136 - 84.7 = 51.3
By what percentage has 136 decreased?
Answer: By ≈ 37.72%
By what percentage is 84.7 smaller than 136?
Answer: By ≈ 37.72%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).