Mathematics: Class 2 — Chapter 7: Rani's Gift

Raja Jagdeep wanted to make a beautiful carved bed for his queen. He requested a bed that was $10$ handspans long.

• The carpenter measured $10$ handspans using his own hand and built the bed.
• When the queen tried to lie down, she could not fit because the bed was too short.
• When the King measured the bed, it was only $8$ handspans long by his measurement.
• When the young apprentice measured it, it was $14$ handspans long.

Key Lesson: A handspan is a non-standard unit of measurement. Because different people have different hand sizes, measuring with handspans leads to inconsistent results.

Practice measuring everyday classroom objects using your textbook or handspan to compare estimated length versus actual length:

• Desk: Estimate the length and then measure the actual length.
• Blackboard: Estimate and measure the actual length.
• Window: Estimate and measure the actual length.

When traveling from one point to another, different routes have different lengths:

• Kavita's Path to School: Choosing the straightest, most direct path helps reach the destination fastest (shortest path).
• Grid Paths: Comparing different paths from point $A$ to point $B$ on a grid to identify the longest and shortest routes. You can verify the length of these paths using a piece of thread.

Using uniform objects like blocks allows us to measure and compare heights accurately.

• The height of different toy animals can be measured by stacking blocks next to them:
• Giraffe: Measured in blocks tall.
• Monkey: Measured in blocks tall.
• Elephant: Measured in blocks tall.

Vegetables can be compared based on their weight:

• Terms used: heavier, lighter, heaviest, and lightest.
• A pumpkin is heavier than a watermelon, while a capsicum is lighter than a cauliflower.

A balance scale is used to compare the weights of two objects.

• The side of the balance with the heavier object goes down.
• The side of the balance with the lighter object goes up.
• You can make your own simple balance scale using a clothes hanger, thread, and two paper cups.

To make $1$ glass of nimbu pani, the following ingredients are needed:

• Water: $1$ glass
• Sugar: $1$ spoon
• Lemon juice: $2$ spoons
• Salt: $1$ pinch

To make $3$ glasses of nimbu pani for friends, we must scale the ingredients by multiplying by $3$:

• Water: $1 \times 3 = 3$ glasses
• Sugar: $1 \times 3 = 3$ spoons
• Lemon juice: $2 \times 3 = 6$ spoons
• Salt: $1 \times 3 = 3$ pinches

Different bottles hold different amounts of water. We can measure their capacity using a standard cup or glass:

• Find out how many glasses of water are needed to completely fill your bottle versus your friend's bottle.
• Jal Tarang: An instrument made by filling $5$ to $7$ similar glasses with varying levels of water. Tapping them with a spoon produces different musical sounds based on the water level.