To increase an amount by 3% what single multiplier would you use
The multiplier would be 1.03 because 1 is a whole and you are increasing by 3 therefore the answer would be 1.03
If you were decreasing an amount then you would take that amount away from 100. Eg - decrease an amount by 50%. What multiplier would you use? The answer to this would be 0.50 because you are taking away 50 from 100.
Hope this helps :)