multiply the original price by the decimal of 30% then x 100 Lets say the item was £10 original price = 0.30 / £10 = 0.3 x 100 =£3 Then £3 is the discount of £10=£7 The second way is easier for smaller numbers 10% of £10 = 1 and then 1 x 3 =3 =£3 discount = £7 new price.
