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 = 7, v2 = - 2.7.
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: - 57.
- Choose a random positive number for the end value: 73.
Formula and calculation:
(v1 - v2) / v1 =
(- 57 - 73) / - 57 =
-130 / - 57 ≈
2.280701754386 ≈
2.28
Although the absolute difference is negative: -130, the relative decrease change is positive: 2.28. 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:
(7 - (- 2.7))/|7| =
(7 + 2.7)/|7| =
9.7/7 =
9.7 ÷ 7 =
9.7 ÷ 7 × 100/100 =
(9.7 × 100 ÷ 7)/100 =
(970 ÷ 7)/100 ≈
138.571428571429/100 =
138.571428571429% ≈
138.57%
(Rounded off to max. 2 decimal places)
The relative percent decrease change
from the original, initial value 7 to the final, end value - 2.7:
Rounded off to max. 12 decimal places ≈ 138.571428571429%
Rounded off to max. 2 decimal places ≈ 138.57%
The absolute (actual) difference
7 + 2.7 = 9.7
By what percentage has 7 decreased?
Answer: By ≈ 138.57%
By what percentage is - 2.7 smaller than 7?
Answer: By ≈ 138.57%
The relative percent decrease change is positive,
so we really have a relative percent decrease
(the value goes down).