(1 - 80%) × 250 = ? Percentage decrease change: Decrement the number 250 by 80% (percent) of its value and Calculate the actual change (the absolute difference)
Decrease the number 250 by 80% of its value
A brief introduction. Definitions and formulas
Percent, p%
'Percent (%)' means 'out of one hundred':
80% = 80 'out of one hundred',
p% is read p 'percent',
p% = p/100 = p ÷ 100
80% = 80/100 = 80 ÷ 100 = 0.8
100% = 100/100 = 100 ÷ 100 = 1
How to decrease the number 250 by 80% of its value?
The value of the percentage decrease = 80% × 250
The new value = 250 - The value of the percentage decrease
Detailed calculations and the calculation proof
1. Calculate the new value of the number... ... decreased by percentage of its initial value
The new value =
250 - The value of the percentage decrease =
250 - (80% × 250) =
250 - 80% × 250 =
(1 - 80%) × 250 =
(100% - 80%) × 250 =
20% × 250 =
20 ÷ 100 × 250 =
20 × 250 ÷ 100 =
5,000 ÷ 100 =
50
2. Calculate the actual change (the absolute difference)... ... between the new value and the initial one
The actual change =
The new value - 250 =
50 - 250 =
- 200
Proof of calculation
We will prove below that the calculations are correct:
Calculate the value of the percentage decrease and see if we get as a result the actual change (the absolute difference) between the new value and the initial one.
For positive numbers, the actual change = - 1 × The value of the percentage decrease
Calculate the value of the percentage decrease:
The value of the percentage decrease =
80% × 250 =
80 ÷ 100 × 250 =
80 × 250 ÷ 100 =
20,000 ÷ 100 =
200
The value of the percentage decrease = - 1 × The actual change =>
In conclusion, the calculations are correct.
The answer:
250 decreased by 80% of its value = 50 The actual change: 50 - 250 = - 200
The symbols used: % percent, ÷ division, × multiplication, = the equal sign, / the fraction bar, ≈ approximately the same. Writing numbers: comma ',' - as a thousands separator, point '.' as a decimal mark.
The latest 5 numbers decreased by percentages of their values
Percentage decreased number = 0.8 × Initial value, and Initial value = Percentage decreased number / 0.8; Absolute percentage change (difference) = New value - Initial value;
Percentage decreased number = 0.95 × Initial value, and Initial value = Percentage decreased number / 0.95; Absolute percentage change (difference) = New value - Initial value;
Percentage decreased number = -0.2 × Initial value, and Initial value = Percentage decreased number / -0.2; Absolute percentage change (difference) = New value - Initial value;
Percentage decreased number = 1.3 × Initial value, and Initial value = Percentage decreased number / 1.3; this is in fact a percentage increase of the initial number; Absolute percentage change (difference) = New value - Initial value.