Percentage Calculations
Break percentages into easy pieces. Use 10%, 5%, and 1% as building blocks. Then combine them to get anything else.
10%
Move the decimal one place left
10% of 80 = 8
10% of 250 = 25
5%
Half of 10%
5% of 80 = 4
5% of 250 = 12.5
1%
Move the decimal two places left
1% of 80 = 0.8
1% of 250 = 2.5
15% of 80
10% + 5% = 8 + 4 = 12
20% of 80
10% × 2 = 8 × 2 = 16
25% of 80
10% × 2 + 5% = 16 + 4 = 20
75% of 80
100% − 25% = 80 − 20 = 60
15% of 80 = 80% of 15
Both equal 12
Simply we manipulate known percentages in order to contruct the desired one.