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What is Identifying Key Information in a Word Problem?
Grade Level:
Class 3
Maths, NLP, AI, Logic, Reading
Definition
What is it?
Identifying key information in a word problem means finding the important numbers and words that tell you what to do. It's like finding the main ingredients in a recipe to know what dish you are making. This helps you understand what the problem is asking and what steps you need to take to solve it.
Simple Example
Quick Example
Imagine your school bus travels 15 km to reach school. If your friend's house is 5 km from school, how far is your friend's house from your home? Here, the key information is '15 km to reach school' and '5 km from school'. These numbers and phrases tell you about distances you need to work with.
Worked Example
Step-by-Step
Problem: Rina bought 3 packets of biscuits. Each packet has 10 biscuits. She ate 2 biscuits from one packet. How many biscuits are left in total?
Step 1: Read the problem carefully to understand the story.
---Step 2: Find the numbers: '3 packets', '10 biscuits', '2 biscuits'.
---Step 3: Find the important words that tell you what to do: 'bought', 'each packet has', 'ate', 'how many are left'.
---Step 4: Identify what the question is asking: 'How many biscuits are left in total?'
---Step 5: Use the key information to plan: First, find total biscuits (3 packets * 10 biscuits/packet). Then, subtract the biscuits eaten (2 biscuits).
---Step 6: Total biscuits = 3 * 10 = 30 biscuits.
---Step 7: Biscuits left = 30 - 2 = 28 biscuits.
Answer: 28 biscuits are left in total.
Why It Matters
Identifying key information is like being a detective for numbers. It helps you solve not just maths problems, but also understand instructions in real life, like assembling a toy or following a cooking recipe. In advanced fields like Artificial Intelligence and Natural Language Processing, computers learn to do this to understand human language and solve complex tasks.
Common Mistakes
MISTAKE: Focusing only on numbers and ignoring important words like 'each', 'total', 'difference'. | CORRECTION: Highlight both the numbers AND the action words (verbs) that tell you what to do with those numbers.
MISTAKE: Picking up extra information that is not needed to solve the problem. | CORRECTION: After identifying numbers and action words, ask yourself, 'Is this piece of information directly helping me answer the question?' If not, it's extra.
MISTAKE: Not reading the question at the end of the problem carefully. | CORRECTION: Always read the final question twice. Sometimes, you might do calculations but answer a different question than what was asked.
Practice Questions
Try It Yourself
QUESTION: A chaiwala sold 50 cups of chai on Monday and 75 cups on Tuesday. How many cups did he sell in total over these two days? | ANSWER: 125 cups
QUESTION: Your mom bought a 5 kg bag of rice. She used 2 kg for dinner and 1 kg for lunch. How much rice is left in the bag? | ANSWER: 2 kg
QUESTION: An auto-rickshaw charges Rs. 10 for the first kilometer and Rs. 5 for every kilometer after that. If you travel 4 kilometers, what will be the total fare? | ANSWER: Rs. 25
MCQ
Quick Quiz
In the problem: 'A cricket team scored 180 runs in the first innings and 215 runs in the second innings. They lost the match by 10 runs. How many runs did they score in total?' Which piece of information is NOT needed to find the total runs scored?
180 runs in the first innings
215 runs in the second innings
lost the match by 10 runs
How many runs did they score in total?
The Correct Answer Is:
C
To find the total runs scored, you only need the runs from the first and second innings (180 + 215). The information about 'lost the match by 10 runs' is extra and not needed for this specific question.
Real World Connection
In the Real World
When you use a food delivery app like Swiggy or Zomato, the app needs to identify key information like your address, the restaurant's location, and the items you ordered. This helps it calculate delivery time, total cost, and send the right order to you. Even ISRO scientists identify key data from satellite signals to understand weather patterns or track rockets.
Key Vocabulary
Key Terms
KEY INFORMATION: The important numbers and words needed to solve a problem | WORD PROBLEM: A maths problem told as a story | UNNECESSARY INFORMATION: Data given in a problem that is not needed to find the answer | QUESTION: What the problem is asking you to find
What's Next
What to Learn Next
Great job learning to find key information! Next, you can learn about 'Choosing the Right Operation in Word Problems'. This will teach you how to decide if you need to add, subtract, multiply, or divide using the key information you've identified.
