Samacheer Kalvi Class 4 Maths Solutions Term 1 Chapter 6 Information Processing Exercise 6.1

Question 1. 9, 7, 2 How many possible ways to write three digit number without repeating. these numbers?
Answer: You can write the following three-digit numbers without repeating any digit: 972, 792, 279, 297, 729, 927. In total, there are 6 possible ways to arrange these three unique digits into a three-digit number. This involves choosing a digit for each of the three places.
In simple words: Using the numbers 9, 7, and 2, you can make 6 different three-digit numbers where no digit is used more than once.

🎯 Exam Tip: For problems involving forming numbers with unique digits, listing them systematically helps ensure all combinations are covered without repetition or omission.

Question 2. In a hotel you have to choose a tiffin and a drink. Here is the list.

List the possible combinations systematically.
Answer: To find all possible combinations, we pair each tiffin option with each drink option.
Idly - Tea
Idly - Coffee
Idly - Milk
Poori - Tea
Poori - Coffee
Poori - Milk
Dosai - Tea
Dosai - Coffee
Dosai - Milk
Pongal - Tea
Pongal - Coffee
Pongal - Milk
There are 4 types of tiffin and 3 types of drinks, making a total of 4 x 3 = 12 possible combinations.
In simple words: You just match each food item (idly, poori, dosai, pongal) with every drink (tea, coffee, milk) to see all the different meals you can have.

🎯 Exam Tip: When listing combinations, use a systematic approach (e.g., fix one item and vary the other) to ensure no possibilities are missed.

Question 3. kavin has four cards 9 7 4 6
a. List down all 3-digit numbers possible with these cards without repetition.
Answer: The 3-digit numbers that can be formed using the cards 9, 7, 4, 6 without repeating any digit are:
974, 946, 976, 964, 947, 967
794, 746, 796, 764, 749, 769
497, 476, 469, 479, 467, 496
697, 679, 674, 647, 694, 649
There are 24 such numbers in total. Each number has three unique digits from the given set of four.
In simple words: You can make many different three-digit numbers using the cards 9, 7, 4, and 6, just make sure not to use the same number twice in one three-digit number.

🎯 Exam Tip: When listing all possible numbers, it is helpful to start with each digit in the hundreds place and systematically list all permutations to avoid missing any combinations.

b. What is the largest 4-digit odd number that can be mode without repeating the numbers?
Answer: To form the largest 4-digit number, we should use the largest digits first. The available digits are 9, 7, 4, 6. For the number to be odd, its last digit must be either 9 or 7. Starting with the largest possible digits in the thousands, hundreds, and tens places, and ending with an odd digit gives us 9647. If we tried to end with 9 (e.g., 7649), the number would be smaller.
In simple words: The biggest four-digit odd number you can make from 9, 7, 4, 6 without using any digit twice is 9647.

🎯 Exam Tip: To create the largest number, always place the largest available digits in the leftmost positions (higher place values) and ensure the last digit meets any specific conditions, like being odd.

Question 4. There are 6 sprinters(an athlete who runs fast in short race). In how many different ways 3 medals(Gold, silver and bronze) be allocated?
Answer: There are 6 sprinters, and 3 distinct medals (Gold, Silver, Bronze) are to be allocated. This is a permutation problem because the order of medals matters (Gold is different from Silver).
For the Gold medal, there are 6 possible sprinters.
After giving the Gold medal, 5 sprinters remain for the Silver medal.
After giving the Silver medal, 4 sprinters remain for the Bronze medal.
So, the total number of ways to allocate the medals is \( 6 \times 5 \times 4 = 120 \) ways. This calculation shows the number of unique sequences for assigning the three medals.
In simple words: If you have 6 sprinters and 3 different medals to give out, you can give them out in 120 different ways. This is because who gets which medal matters.

🎯 Exam Tip: When the order of selection matters (like first, second, third place, or different medals), use permutations. If order doesn't matter (like choosing a group of people), use combinations.