This deep dive covers Universal Percentage Problem Method within Percentage Problems for GCSE Mathematics. Revise Percentage Problems in Number for GCSE Mathematics with 14 exam-style questions and 22 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 3 of 8 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Universal Percentage Problem Method
The PIER Method:
- Problem - What type of percentage problem is this?
- Identify - What's the original amount and what's the percentage?
- Execute - Apply the correct formula or method
- Review - Does your answer make sense in context?
Key Techniques:
- Multiplier Method: Increase by 15% → multiply by 1.15
- Decrease by 30% → multiply by 0.7
- Reverse Percentages: If £84 is after 20% VAT, original = £84 ÷ 1.2 = £70
- Multiple Changes: Apply each percentage change step by step
Practice questions for Percentage Problems
What is the multiplier for a 30% increase?
Work out 20% of 60.
Quick recall flashcards
What is the formula for simple interest?
I = PRT/100
where P = Principal, R = Rate (%), T = Time (years)
A £60 item has 25% off. What do you pay?
Method 1: Discount = £60 × 0.25 = £15, Pay = £60 - £15 = £45
Method 2: Pay = £60 × 0.75 = £45
Answer: £45