Detailed calculations below
Introduction. Percent, p%
'Percent (%)' means 'out of one hundred':
p% = p 'out of one hundred',
p% is read p 'percent',
p% = p/100 = p ÷ 100.
100% = 100/100 = 100 ÷ 100 = 1.
Relative change. Definition:
Relative change is the difference in an indicator over two periods in time, v2 - v1, relative to the value of the indicator in the earlier period, v1.
Namely:
v1 - is called the reference value (original, initial number);
v2 - is called the new value.
In our case: v1 = 984, v2 = - 1.
Relative change. Formula:
(v2 - v1) / |v1| =
Actual change / |v1|
Legend:
v1 - original number
|v1| - positive value of v1, |v1| >= 0
v2 - new value
Actual change = v2 - v1
/ - fraction bar, division bar:
Actual change / |v1| = Actual change ÷ |v1|
Why using |v1| in the formula, instead of v1?
Calculate the Relative change by using v1 instead of |v1|:
Pick a random negative as original number: - 63.
Pick a random positive as the new value: 79.
Formula:
(79 - (- 63)) / - 63 =
(79 + 63) / - 63 =
142 / - 63 ≈
- 2.253968253968 ≈
- 2.25
Though the actual change is positive: 142,
... the relative change is negative: - 2.25. Not good!
By using |v1| instead of v1, the error is corrected.
Note:
Multiply a number by the fraction 100/100,
... and its value doesn't change.
100/100 = 100% = 100 ÷ 100 = 1.
n/100 = n%, any number.
Relative percent change. Formula:
Relative percent change =
Relative change × 100/100 =
(Relative change × 100)/100 =
(Relative change × 100)% =
Calculate the Relative percent change:
(- 1 - 984)/|984| =
- 985/984 =
- 985 ÷ 984 =
- 985 ÷ 984 × 100/100 =
(- 985 × 100 ÷ 984)/100 =
(- 98,500 ÷ 984)/100 ≈
- 100.10162601626/100 =
- 100.10162601626% ≈
- 100.1%;
Relative percent change is negative,
so in this case we have a relative percent decrease.
Answer:
:: written in two ways ::