Question

How do you decrease £840 by 5%

Answer 1

 £840  -   100%
100%-5%=95%
840*95%:100% = 798 (£) - the number sought

Answer 2

To decrease by percentages you do 100 minus the percent you want to take away. In this case it's 100-5=95. Then divide 95 by 100 which is 0.95. This is the multiplier. Finally, times the multiplier by the number for your answer. In this situation it's 0.95*840=798. The answer is £798.