- Percentage Increase & Decrease
- Home
- Finding the final amount given the original amount and a percentage increase or decrease
- Finding the sale price given the original price and percent discount
- Finding the sale price without a calculator given the original price and percent discount
- Finding the total cost including tax or markup
- Finding the original amount given the result of a percentage increase or decrease
- Finding the original price given the sale price and percent discount
- Comparing discounts

- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who

In this lesson, we learn how to find a sale price, given the original price and a percent discount without a calculator.

**Rules for finding the sale price given the original price and percent discount**

At first, we consider the original price and discount rate.

The rate is usually given as a percent.

To find the discount, multiply the rate by the original price.

To find the sale price, subtract the discount from original price

For finding the sale price without a calculator we use mental math methods as shown in the solved examples below.

A shirt is put on sale for 40% off the regular price. If the regular price is $90

what is the sale price?

**Step 1:**

Regular price = $90

Discount percent = 40% off $90;

**Step 2:**

10% of 90 can be found by shifting the decimal point one place to left as $9.0. 40% of $90 is 4 times this amount, i.e., 4 × $9.0 = $36.0

So, discount = $36.0

**Step 3:**

Sale price = Original price – Discount = $90 – $36 = $54

A dress is put on sale for 20% off the regular price. If the regular price is $110 what is the sale price?

**Step 1:**

Discount percent = 20% off $110;

**Step 2:**

At first, we find the 10% of $110.0. Here we shift the decimal one place to left and get $11.0. To find 20% we double this amount as 2 × $11 = $22

So, Discount = $22

**Step 3:**

Sale price = Original price – Discount = $110 − $22 = $88

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