By John Smith
Updated Aug 30, 2022
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While mental math is handy, precise calculations are essential for budgeting, invoices, or price negotiations. To reduce a figure by a percentage, simply multiply the original amount by the remaining percentage expressed as a decimal. For example, to subtract 20%, multiply by 0.8 (80%). To subtract 30%, use 0.7 (70%).
Before you start, decide whether you’re working with the pre‑tax amount or the total that already includes taxes and fees. Subtracting a discount from a pre‑tax figure gives a clearer picture of the final cost.
1. Enter the amount you wish to reduce. For illustration, let’s use $85.50.
2. Press the multiplication button (×).
3. Input 0.8 to represent 80% and press equals. The result is $68.40 (85.50 × 0.8 = 68.40).
