# Elephants, Tigers and Leopards

## Overview

This chapter builds mathematical understanding through games, word problems, number patterns, addition-subtraction operations, estimation, data handling, and logic-based puzzles. Children engage with contextual problems related to wildlife data in India, develop strategies for mental math, and reinforce place value concepts.

## Key Topics Covered

### 1. **NIM Game – 2 Player Strategy Game**

* A game where players alternately add 1 or 2 to reach a target number (like 10).
* Helps develop logic and prediction strategies.
* Questions posed to test winning positions if the opponent is at 6, 7, or 8.

### 2. **Exploring Patterns – Addition Chart**

* A 13×13 addition grid from 0 to 12.
* Activities include:

* Finding how often certain numbers appear (like 9).
* Observing rows/columns with even/odd numbers.
* Analyzing sums across rows, columns, and diagonals using colored window frames.
* Promotes pattern recognition and algebraic thinking.

### 3. **Reverse and Add**

* Choose a 2-digit number, reverse it, and add.

* Example: 27 → 72 → 27 + 72 = 99
* Activities:

* List combinations where sums = 55 or 88.
* Explore smallest 3-digit sums.
* Builds understanding of digit reversal and number properties.

### 4. **How Many Animals? – Word Problems**

* Real data about elephants, tigers, and leopards is used to create multi-digit addition problems.

* Example: Elephants in Karnataka (6049) + Kerala (3054) = 9103
* Leopards in Gujarat, Karnataka, and Madhya Pradesh: Total = 4303
* Concepts of carrying and regrouping used and explained.

### 5. **More or Less – Subtraction**

* Comparative problems involving animals across states.

* Assam has 3965 more elephants than Meghalaya. Total in Assam = 5719 → Meghalaya = 1754
* Leopard population increased by 749 from 2018 to 2022 → find 2018 population.
* Focus on estimation, subtraction with regrouping.

### 6. **Data Handling – Visitors and Juice Bottles**

* Interpreting monthly visitors to Kaziranga National Park.
* Estimating October visitors based on November and December data.
* Problem-solving with juice bottle production data:

* Guava juice = 759 more than pineapple juice (1348)
* Orange juice = more than guava, less than passion fruit
* Compare sums of different juice types.

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Here is the second part of the mathematics chapter summary:

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### 7. **Vehicles in Town – Logical Word Problems**

* Given numbers and differences between vehicle types:

* Buses = Jeeps + 253
* Tractors = Buses − 5247
* Taxis = Tractors + 1579
* Arrange vehicle counts in increasing order.
* Focus on logical reasoning, sequencing, and difference-based subtraction.

### 8. **Basic Operations Practice**

#### A. Addition:

* Example sums:

* 1459 + 476 = 1935
* 3863 + 4188 = 8051
* Practice includes both mental math and column method.

#### B. Subtraction:

* Example sums:

* 7293 – 2819 = 4474
* 3105 – 1223 = 1882

#### C. Mixed operations and strategy-based calculations:

* Use rounding, compensating, or friendly numbers.
* Compare results using `<, =, >` without solving.
* Example reasoning: 4596 + 104 > 4596 + 103

### 9. **Money Math – Deposit Slip**

* Fill a bank deposit slip using denominations of ₹500, ₹100, ₹50, ₹10, ₹5, ₹2, ₹1.
* Total money = ₹2045, etc.
* Emphasizes:

* Breakdown of amounts into denominations.
* Practical knowledge of currency handling.

### 10. **Puzzles and Reasoning**

* Square grid: Fill with numbers 1–9 so adjacent boxes differ by an odd number (or even).
* Encourages exploration, pattern making, and trial-error strategy.

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## New Terms (with simple meanings)

| Term | Definition |
| ------------ | ------------------------------------------------------------------ |
| Estimate | To guess the approximate value |
| Regrouping | Rearranging numbers while adding/subtracting to carry/borrow |
| Diagonal | A line joining opposite corners of a square or rectangle |
| Strategy | A smart plan to win or solve something |
| Census | An official count of population (animals or people) |
| Denomination | The value printed on a currency note or coin |
| Onomatopoeia | A word that imitates the sound it describes (e.g., moo, cluck) |
| Reverse | To change the order (e.g., reverse of 21 is 12) |
| Pattern | A repeated arrangement of numbers or shapes |
| Biodiversity | Variety of living things in a region (like animals, birds, plants) |

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## Practice Questions

### Easy (3)

1. **Add**: 1243 + 214
**Answer**: 1457
**Explanation**: Add ones, tens, hundreds, then thousands.

2. **Subtract**: 845 – 237
**Answer**: 608
**Explanation**: Use column subtraction with borrowing.

3. **Find the missing number**: \_\_\_ + 198 = 453
**Answer**: 255
**Explanation**: Subtract 198 from 453.

### Medium (2)

4. If a tiger reserve has 1236 tigers and another has 2134 tigers, how many in total?
**Answer**: 3370
**Explanation**: Add using standard algorithm.

5. The number 68 is how much less than 120?
**Answer**: 52
**Explanation**: 120 – 68 = 52.

### Difficult (3)

6. A juice factory makes 1348 pineapple, 2107 guava and 3253 orange juice bottles. What is the total?
**Answer**: 6708
**Explanation**: 1348 + 2107 + 3253 = 6708

7. If Raju has ₹2045 made of 3 × ₹500, 3 × ₹100, 2 × ₹50, 14 × ₹10, and 1 × ₹5, verify the amount.
**Answer**: ₹2045
**Explanation**: (3×500)+(3×100)+(2×50)+(14×10)+5 = ₹2045

8. A bus depot has 6304 jeeps. If there are 253 more buses than jeeps, how many buses?
**Answer**: 6557
**Explanation**: 6304 + 253 = 6557

### Very Difficult (2)

9. In 2022, there were 8820 leopards. If that’s 749 more than in 2018, how many in 2018?
**Answer**: 8071
**Explanation**: 8820 – 749 = 8071

10. Fill the squares with 1–9 such that adjacent numbers differ by **odd** values. Try at least one correct combination.
**Answer**:

```
1 4 7
6 9 2
3 8 5
```

**Explanation**: All neighboring differences are odd (like 4−1=3, 9−6=3).

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