![]() ![]() The first two teaching strategies focus on developing the meaning and equivalence of adding percentages and multiplying by the appropriate decimal. They will not know they can multiply the pay by (1 - 0.27). To find their pay if 27% is subtracted for tax, they will calculate the tax and subtract from the pay. They will not know they can multiply the original price by (1 + 0.17). For example, to find the price after a 17% mark-up has been added to a wholesale price of $80, they will find the mark up ($80 × 0.17 = $13.60) and then add to get the final price ($80 + $13.60). ![]() Illustration 1: Adding percentages by multiplication by a decimalĪt this stage, students will already be able to calculate the result by calculating the mark up first. For more information,įor more information, see: More about adding Percentages - (Level 5.25) Success at this level depends on students being able to add or subtract a percentage in one step by multiplication.įor example, to find a selling price after a 17% mark-up has been added, multiply by (1 + 0.17) to find a sale price when a 30% discount is given, multiply by (1 - 0.30). Many students will do this by calculating the mark-up or discount separately, and then adding or subtracting from the price. A very common use of percentages is to increase or decrease a given amount by a percentage. ![]()
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