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PSLE Word Problems: The K-U-S Method

Our signature 'Known-Unknown-Solve' method for tackling high-weightage P6 word problems.

The PSLE Word Problems guide introduces our signature K-U-S (Known-Unknown-Solve) method — a systematic approach designed to eliminate the 'blank-out' moments that students experience when facing complex, multi-step word problems. It covers problem identification (Equal Stage, External Change, Total Change, Remainder Concept) and provides a structured execution framework for the highest-weighted questions in PSLE Paper 2.

Step 1: The 'K-U-S' Method

K (Know): Highlight or list down the key given numbers, entities, and keywords (e.g., 'more than', 'ratio', 'constant', 'remainder')

U (Underline): Underline the exact final question (e.g., 'Find the number of cards Ali had at first'). Prevents the common error of calculating the final instead of initial amount

S (Strategy): Match keywords to the correct heuristic (e.g., 'equal total at first' => make total ratio units equal; 'remainder' => use branching)

Step 2: Identifying Problem Types

Equal Stage (Internal Transfer): 'Ali gave John 20 cards, and they now have an equal number'. Total sum remains constant. Make the sum of ratio units equal before and after

External Change (One Parameter Constant): 'Ali spent $15, John spent nothing. Ratio changed'. John's quantity is constant. Make John's ratio units equal in the before and after ratios

Total Change (All Quantities Change): 'Both received different amounts'. Use units and parts, simultaneous equations, or stacking model drawing

Step 3: Execution & Patterns

Branching Diagram: Used for 'fraction of remainder' problems. The branch starts at Total, splits into Used and Remainder. The Remainder then splits again. Work from the bottom up

Constant Difference (Age/Intervals): 'Father is 30 years older than Son. In 5 years, father is 3 times son's age'. Make the difference between ratio units equal

Units and Parts (Algebraic Ratios): Write equation system where u represents initial units and p represents final parts. Solve for 1 unit

Step 4: The Final Check

Units Check: Ensure final answers have correct units written ($, kg, cm, m/s)

Reasonableness Test: Check if the value is physically possible. People must be integers, speeds must be positive, etc

Reverse Verification: Plug the final answer back into the start of the word problem to check if it satisfies all constraints

Frequently Asked Questions

What is the K-U-S method for PSLE word problems?▾

K-U-S stands for Known-Unknown-Solve. Step 1 (Know): highlight the keywords and given values. Step 2 (Underline): underline exactly what the question is asking. Step 3 (Strategy): choose the best approach — Model Drawing, Units, or Algebra. This systematic method prevents students from blanking out on complex questions.

What types of PSLE word problems does this guide cover?▾

It covers four major PSLE word problem patterns: Equal Stage (where quantities become equal), External Change (where only one party's quantity changes), Total Change (where all quantities change), and Remainder Concept (fractions of remainders). These patterns account for the vast majority of 4-5 mark PSLE questions.

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