31. Give your Mind a Workout!
Notes and answers for the games, number trick, puzzle and jokes — Maharashtra State Board (Balbharati), Grade Five English.
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About this chapter: This is an activity chapter with games, a number trick, a puzzle and jokes, and it has no numbered exercise questions. The notes below explain each item in simple words, with answers and examples for the “find out” tasks.
This is a game to play with a friend. Draw the board on paper (squares one inside another, joined by lines) and use buttons, beads or seeds of two different kinds as pieces.
- Two players play. Each player has nine pieces (‘men’) of one kind.
- Placing: Players take turns to place one piece at a time on an empty spot of the board.
- Mill: If you place three of your men in a straight row or column, you form a ‘mill’. You may then remove one of your opponent’s men. You cannot remove a man that is part of the opponent’s mill unless the opponent has no other men on the board.
- Moving: When all the men have been placed, players take turns to move one man to an adjacent empty spot.
- Flying: A player who has only three men left may ‘fly’, that is, move a man to any empty spot on the board.
- Winning: A player who has fewer than three men left, or who cannot make a move, loses the game.
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Take any three-digit number whose first and last digits differ by two or more, and follow these steps.
- Write the number in reverse order (for example, 145 becomes 541).
- Subtract the smaller number from the bigger one: 541 − 145 = 396.
- Reverse the difference: 396 becomes 693.
- Add the two numbers: 396 + 693 = 1089.
Try another number, 832: 832 − 238 = 594, and 594 + 495 = 1089. The answer is always 1089.
Why it works: The difference of a number and its reverse is always a multiple of 99 (99 times the gap between the first and last digits). When the gap is two or more, this difference is a three-digit number whose middle digit is 9 and whose first and last digits add up to 9. Adding it to its own reverse therefore always gives 1089.
Task: Find other tricks with numbers with the help of your parents, teachers or the internet. Here is one to start with: think of any number, double it, add 10, halve the result, then subtract the number you started with. The answer is always 5.
There are two possible explanations.
- Along with the last pencil, Pintu gave the box itself to one of his friends. So that friend has the pencil inside the box, and it looks as if one pencil is still “in the box”.
- One of the friends forgot to take his pencil, so Pintu put it back in the box.
Task: Find more puzzles and riddles from books, magazines or the internet. Here is one to start with: “What has hands but cannot clap?” The answer is a clock.
The guava joke
The teacher expects the answer “half of it”, because the guava is to be shared equally. Ananya cleverly says she will get all of it, since her younger sister does not like guavas and will not take any. The surprise in her answer is what makes it funny.
The environment joke
The teacher asks who makes changes in his environment, and she means that all of us do, for example by building houses or cutting trees. Saurav thinks he is being blamed and says, “I didn’t do anything!”. The joke is his funny misunderstanding of the question.
Task: Find other jokes related to your school subject from magazines, books or the internet. Here is one to start with: “Why was the maths book sad? Because it had too many problems.”