 A fraction where the denominator is always 100 is called a percentage. There is a 30% reduction of an item worth 50 pounds. By how much has the item been reduced? We need to calculate 30% of 50 pounds and take away that figure from the 50 pounds. We can do this using the number strip by splitting 50 pounds into 10 equal parts. If the whole strip is 100% then one part is 10%. 10% of 50 pounds equals 5 pounds. So to get 30% we need to multiply 5 pounds by 3. Therefore 30% of 50 pounds is 15 pounds.