Civil Service Exam (Subprofessional) Numerical Ability — Ratio, Proportion & PercentageSlides
The slide format strips Ratio, Proportion & Percentage to the visuals that Civil Service Exam (Subprofessional) reviewers remember best. Civil Service Commission (CSC)'s 2026 Numerical Ability papers reward reviewers who recognise the structure of a concept before they parse the item text; these slides train that recognition.
Exam context
Civil Service Commission (CSC) runs the Career Service Examination — Subprofessional Level on Bi-annual — March and August 2026. Its Numerical Ability section sits under a "~25% weightage" weighting, and Ratio, Proportion & Percentage is the 4th chapter in the 9-chapter Civil Service Exam (Subprofessional) Numerical Ability rotation. The Civil Service Exam (Subprofessional) passing mark is 80%, and the most recent 2026 paper drew about 17 questions from Numerical Ability.
Ratio, Proportion & Percentage - Slides
This chapter covers fundamental concepts of ratio, proportion, and percentage that are essential for numerical ability and problem-solving in various competitive exams in the Philippines. Students will learn to understand relationships between quantities, solve proportion problems, work with percentages, and apply these concepts to real-world scenarios including discount, tax, profit, and depreciation problems.
Slides
Chapter Overview: Ratio, Proportion & Percentage
This chapter forms the foundation for numerical reasoning skills required in UPCAT, CSE, LET, NLE, NMAT, ACET, and USTET examinations. We'll explore how ratios express relationships, proportions show equality of ratios, and percentages represent parts of a whole.
Notes
Emphasize the interconnected nature of these three concepts and their practical importance in Philippine exam contexts.
Topic
Chapter Overview
Slide Id
S1
Visual Type
mermaid
Image Prompt
Slide Number
1
Mermaid Diagram
Code
mindmap root((Ratio Proportion Percentage)) Ratio Definition Types Applications Proportion Cross Multiplication Problem Solving Three Terms Percentage Basic Calculations Finding Rate Finding Base Applications Discount and Tax Profit and Loss Depreciation Real World Problems
Type
mermaid_mindmap
Description
Mind map showing the main components and relationships within ratio, proportion, and percentage concepts
Understanding Ratio
A ratio is a comparison of two quantities by division. It tells us how much of one thing there is compared to another. For example, if there are 3 boys and 2 girls in a group, the ratio of boys to girls is 3:2.
Notes
Stress the importance of simplifying ratios and understanding that ratios maintain proportional relationships.
Topic
Ratio Basics
Slide Id
S2
Visual Type
mermaid
Image Prompt
Slide Number
2
Mermaid Diagram
Code
flowchart TD A[Two Quantities] --> B[Compare by Division] B --> C{Can be Simplified?} C -->|Yes| D[Simplify to Lowest Terms] C -->|No| E[Keep Original Ratio] D --> F[Express as a:b] E --> F F --> G[fa:fa-check Final Ratio]
Type
mermaid_flowchart
Description
Flowchart showing the process of creating and simplifying ratios
Types of Ratios
Different types of ratios serve different purposes in mathematical problem-solving. Simple ratios are most common in everyday applications, while compound and other types appear in more complex mathematical situations.
Notes
Focus primarily on simple ratios as they are most relevant for grade 12 students and Philippine exams.
Topic
Ratio Types
Slide Id
S3
Visual Type
mermaid
Image Prompt
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3
Mermaid Diagram
Code
flowchart TD A[Ratio Types] --> B[Simple Ratio a:b] A --> C[Compound Ratio] A --> D[Duplicate Ratio a²:b²] A --> E[Triplicate Ratio a³:b³] A --> F[Sub-duplicate √a:√b] B --> G[Most Common] C --> H[Product of Ratios] D --> I[Squared Terms] E --> J[Cubed Terms] F --> K[Square Root Terms]
Type
mermaid_flowchart
Description
Classification of different types of ratios and their characteristics
Introduction to Proportion
A proportion is an equation that shows two ratios are equivalent. When we have a proportion a:b = c:d, we can cross multiply to get ad = bc. This property helps us solve for unknown values.
Notes
Emphasize cross multiplication as the key technique for solving proportion problems.
Topic
Proportion Basics
Slide Id
S4
Visual Type
mermaid
Image Prompt
Slide Number
4
Mermaid Diagram
Code
flowchart TD A[Two Equal Ratios] --> B[a:b = c:d] B --> C[Cross Multiply] C --> D[a × d = b × c] D --> E{Unknown Value?} E -->|Yes| F[Solve for Unknown] E -->|No| G[Verify Equality] F --> H[fa:fa-calculator Calculate] G --> H
Type
mermaid_flowchart
Description
Process flow for working with proportions and cross multiplication
Solving Proportion Problems
Proportion problems follow a systematic approach. The key is correctly identifying which quantities are related and setting up the proportion properly before applying cross multiplication.
Notes
Practice with Philippine peso amounts and familiar contexts to make problems more relatable.
Topic
Proportion Problem Solving
Slide Id
S5
Visual Type
mermaid
Image Prompt
Slide Number
5
Mermaid Diagram
Code
sequenceDiagram participant S as Student participant P as Problem participant E as Equation participant A as Answer S->>P: Read problem carefully P->>E: Set up proportion E->>E: Cross multiply E->>A: Solve for unknown A->>S: Verify answer
Type
mermaid_sequence
Description
Sequential steps for solving proportion problems systematically
Understanding Percentages
Percentage is a way of expressing a fraction or decimal as parts per hundred. It's one of the most practical mathematical concepts used daily in shopping, grading, statistics, and financial calculations.
Notes
Connect percentages to familiar Filipino contexts like grades, discounts, and statistics.
Topic
Percentage Basics
Slide Id
S6
Visual Type
mermaid
Image Prompt
Slide Number
6
Mermaid Diagram
Code
pie title Percentage Representation "25%" : 25 "35%" : 35 "40%" : 40
Type
mermaid_pie
Description
Pie chart showing how percentages represent parts of a whole (100%)
Converting Between Fractions, Decimals, and Percentages
Converting between these forms is crucial for percentage calculations. Understanding the relationships helps in choosing the most efficient method for solving problems.
Notes
Practice with common fractions like 1/2, 1/4, 3/4, 1/5, etc., that appear frequently in exams.
Topic
Percentage Conversions
Slide Id
S7
Visual Type
mermaid
Image Prompt
Slide Number
7
Mermaid Diagram
Code
flowchart TD A[Fraction] --> B[× 100] --> C[Percentage] C --> D[÷ 100] --> E[Decimal] E --> F[Move decimal right 2] --> C A --> G[Divide] --> E C --> H[Over 100 and simplify] --> A E --> I[Multiply] --> A
Type
mermaid_flowchart
Description
Conversion relationships between fractions, decimals, and percentages
Finding the Rate (Percentage)
When finding what percentage one number is of another, divide the part by the whole and multiply by 100. This is frequently used in analyzing data, survey results, and determining success rates.
Notes
Use examples from Philippine education and demographics to make problems more relevant.
Topic
Finding Rate
Slide Id
S8
Visual Type
mermaid
Image Prompt
Slide Number
8
Mermaid Diagram
Code
flowchart TD A[Given: Part and Whole] --> B[Divide Part by Whole] B --> C[fa:fa-calculator Result as Decimal] C --> D[Multiply by 100] D --> E[Add % Symbol] E --> F[fa:fa-check Final Answer]
Type
mermaid_flowchart
Description
Step-by-step process for finding the rate or percentage
Finding the Base (Original Amount)
Finding the base means determining the original whole amount when you know what percentage a part represents. This is essential for problems involving original prices, total populations, or initial quantities.
Notes
Emphasize converting percentages to decimals and checking answers for reasonableness.
Topic
Finding Base
Slide Id
S9
Visual Type
mermaid
Image Prompt
Slide Number
9
Mermaid Diagram
Code
flowchart TD A[Given: Part and Rate] --> B[Convert % to Decimal] B --> C[Divide Part by Rate] C --> D[fa:fa-calculator Calculate Base] D --> E{Check Answer} E -->|Reasonable| F[fa:fa-check Final Answer] E -->|Unreasonable| G[fa:fa-times Review Calculation]
Type
mermaid_flowchart
Description
Process for finding the base or original amount from part and rate
Finding the Part (Percentage Amount)
Finding the part involves calculating what amount represents a certain percentage of a base number. This is the most common type of percentage calculation used in shopping, taxes, and tip calculations.
Notes
Use familiar Philippine contexts like restaurant tips, utility bills, and shopping scenarios.
Topic
Finding Part
Slide Id
S10
Visual Type
mermaid
Image Prompt
Slide Number
10
Mermaid Diagram
Code
flowchart TD A[Given: Base and Rate] --> B[Convert % to Decimal] B --> C[Multiply Base × Rate] C --> D[fa:fa-calculator Calculate Part] D --> E[Express with Proper Units] E --> F[fa:fa-check Final Answer]
Type
mermaid_flowchart
Description
Straightforward process for finding the part when base and rate are known
Discount and Tax Applications
Discount and tax calculations are essential life skills. Discounts reduce the price you pay, while taxes increase it. Understanding both helps in budgeting and making informed purchasing decisions.
Notes
Emphasize the 12% VAT rate in the Philippines and common discount percentages in local stores.
Topic
Discount and Tax
Slide Id
S11
Visual Type
mermaid
Image Prompt
Slide Number
11
Mermaid Diagram
Code
flowchart TD A[Original Price] --> B[Apply Discount] B --> C[Sale Price] C --> D[Apply Tax] D --> E[Final Price] B --> F[Multiply by Discount %] F --> G[Subtract from Original] D --> H[Multiply by Tax Rate] H --> I[Add to Sale Price]
Type
mermaid_flowchart
Description
Process flow showing how discounts and taxes are applied to original prices
Profit and Loss Calculations
Profit and loss calculations are fundamental in business and investment analysis. The percentage is always calculated based on the original cost price, not the selling price.
Notes
Use examples with Filipino products and realistic prices to make calculations more meaningful.
Topic
Profit and Loss
Slide Id
S12
Visual Type
mermaid
Image Prompt
Slide Number
12
Mermaid Diagram
Code
flowchart TD A[Cost Price and Selling Price] --> B{Selling > Cost?} B -->|Yes| C[Calculate Profit] B -->|No| D[Calculate Loss] C --> E[Profit = SP - CP] D --> F[Loss = CP - SP] E --> G[Profit % = Profit/CP × 100] F --> H[Loss % = Loss/CP × 100] G --> I[fa:fa-chart-line Result] H --> I
Type
mermaid_flowchart
Description
Decision tree for calculating profit or loss and their respective percentages
Depreciation Concepts
Depreciation represents how assets lose value over time due to wear, age, or obsolescence. Understanding depreciation helps in making informed decisions about purchases and investments.
Notes
Use examples of common Filipino purchases like cars, gadgets, and appliances that students can relate to.
Topic
Depreciation
Slide Id
S13
Visual Type
mermaid
Image Prompt
Slide Number
13
Mermaid Diagram
Code
timeline title Asset Value Over Time Year 0 : Original Value 100% Year 1 : Value Decreases 90% Year 2 : Continued Decline 82% Year 3 : Current Value 75%
Type
mermaid_timeline
Description
Timeline showing how asset value decreases over time due to depreciation
Word Problem Solving Strategies
Word problems require careful analysis to identify the type of calculation needed. Practice helps in recognizing patterns and selecting the correct approach quickly during exams.
Notes
Emphasize the importance of identifying the problem type before attempting to solve.
Topic
Word Problem Strategy
Slide Id
S14
Visual Type
mermaid
Image Prompt
Slide Number
14
Mermaid Diagram
Code
sequenceDiagram participant R as Read participant I as Identify participant C as Choose participant S as Solve participant V as Verify R->>I: Extract given data I->>C: Select formula C->>S: Apply method S->>V: Check answer V-->>R: Reread if needed
Type
mermaid_sequence
Description
Sequential approach to solving word problems systematically
Common Exam Question Types
Philippine competitive exams frequently test these concepts through practical scenarios. Recognizing question patterns helps in applying the correct method quickly and accurately.
Notes
Focus practice on the most common question types to maximize exam performance.
Topic
Exam Question Types
Slide Id
S15
Visual Type
mermaid
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15
Mermaid Diagram
Code
pie title Common Exam Question Distribution "Finding Rate" : 25 "Finding Base" : 25 "Discount Tax" : 20 "Profit Loss" : 15 "Proportions" : 15
Type
mermaid_pie
Description
Distribution of question types commonly found in Philippine competitive examinations
Practice Problems and Solutions
Regular practice with varied problem types builds confidence and speed. Focus on understanding the logic behind each solution rather than just memorizing procedures.
Notes
Encourage students to practice with actual exam questions from past Philippine competitive exams.
Topic
Practice Problems
Slide Id
S16
Visual Type
none
Image Prompt
Slide Number
16
Mermaid Diagram
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none
Key Formulas Summary
These fundamental formulas form the foundation for solving all ratio, proportion, and percentage problems. Memorize them and understand when to apply each one.
Notes
Create a formula sheet for quick reference during practice and review sessions.
Topic
Formula Summary
Slide Id
S17
Visual Type
mermaid
Image Prompt
Slide Number
17
Mermaid Diagram
Code
mindmap root((Key Formulas)) Rate Formula Part ÷ Base × 100% Finding Percentage Base Formula Part ÷ Rate Finding Original Part Formula Base × Rate Finding Amount Proportion Cross Multiply Solve for Unknown Profit Loss Based on Cost Price Percentage Calculation
Type
mermaid_mindmap
Description
Mind map organizing all key formulas by their applications and relationships
Chapter Review and Key Takeaways
This chapter provides essential numerical skills for both academic success and practical life applications. Master these concepts through consistent practice with varied problem types, especially those common in Philippine competitive examinations.
Notes
Encourage continued practice and application of these concepts in daily life situations.
Topic
Chapter Review
Slide Id
S18
Visual Type
none
Image Prompt
Slide Number
18
Mermaid Diagram
Type
none
References
- NCV CIVIL SERVICE — Worded Problems.pdf
- Department of Education Mathematics Curriculum Guide Grade 12
- Philippine Civil Service Commission Examination Guidelines
- University of the Philippines College Admission Test Reviewer
- Professional Regulation Commission Examination Standards
In summary
Ratio, Proportion, and Percentage form the cornerstone of numerical ability required for success in Philippine competitive examinations and practical life applications. Students who master these concepts will find themselves well-prepared for UPCAT, CSE, LET, NLE, NMAT, ACET, USTET, and other important assessments. The key to success lies in understanding the relationships between these concepts, practicing with diverse problem types, and applying systematic problem-solving approaches. Regular practice with Filipino contexts and realistic scenarios will build both confidence and competency in handling numerical challenges.
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