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 = 126, v2 = - 21.
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: - 62.
- Choose a random positive number for the end value: 60.
Formula and calculation:
(v1 - v2) / v1 =
(- 62 - 60) / - 62 =
-122 / - 62 ≈
1.967741935484 ≈
1.97
Although the absolute difference is negative: -122, the relative decrease change is positive: 1.97. 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:
(126 - (- 21))/|126| =
(126 + 21)/|126| =
147/126 =
147 ÷ 126 =
147 ÷ 126 × 100/100 =
(147 × 100 ÷ 126)/100 =
(14,700 ÷ 126)/100 ≈
116.666666666667/100 =
116.666666666667% ≈
116.67%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 126 to the final, end value - 21:
Rounded off to max. 12 decimal places ≈ 116.666666666667%
Rounded off to max. 2 decimal places ≈ 116.67%
The absolute (actual) difference
126 + 21 = 147
By what percentage has 126 decreased?
Answer: By ≈ 116.67%
By what percentage is - 21 smaller than 126?
Answer: By ≈ 116.67%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).