Mathematics: Class 2 — Chapter 6: Decoration for Festival

Based on the number of garlands and loose flowers each child has, we can find the total number of flowers:

• Rohan: $1$ garland and $2$ loose flowers $\rightarrow 10 + 2 = 12$ flowers
• Simran: $3$ garlands and $7$ loose flowers $\rightarrow 30 + 7 = 37$ flowers
• Akash: $4$ garlands and $8$ loose flowers $\rightarrow 40 + 8 = 48$ flowers
• Suwali: $5$ garlands and $3$ loose flowers $\rightarrow 50 + 3 = 53$ flowers
• Javed: $4$ garlands and $3$ loose flowers $\rightarrow 40 + 3 = 43$ flowers
• Zoha: $2$ garlands and $0$ loose flowers $\rightarrow 20 + 0 = 20$ flowers

To find the total flowers used by two friends together, we add their individual counts:

• Rohan and Suwali: $12 + 53 = 65$ flowers.
  Using column addition:
  $$\begin{array}{r@{\quad}l} \text{T} & \text{O} \\ 1 & 2 \\ + \; 5 & 3 \\ \hline 6 & 5 \end{array}$$
• Zoha and Javed: $20 + 43 = 63$ flowers.
• Zoha and Akash: $20 + 48 = 68$ flowers.

• To solve $25 + 12$, start at $25$ and count $12$ beads ahead to reach $37$.
• To solve $57 + 34$, break it down: $57 + 30 + 4 = 87 + 4 = 91$.
• To solve $24 + 43$, break it down: $24 + 40 + 3 = 64 + 3 = 67$.

Jumping on a number line makes addition easier without counting individual beads:

• $23 + 14 = 37$: Start at $23$, take a big jump of $+10$ to reach $33$, then $4$ small steps of $+1$ to reach $37$.
• $24 + 16 = 40$: Start at $24$, jump $+10$ to $34$, then $+6$ to reach $40$.
• $11 + 22 = 33$: Start at $11$, jump $+20$ to $31$, then $+2$ to reach $33$.

Mahi has $2$ tens and $3$ ones ($23$ blocks). Isha has $3$ tens and $8$ ones ($38$ blocks).

• Total ones: $3 + 8 = 11$ ones.
• Regroup $11$ ones into $1$ ten and $1$ one.
• Total tens: $2 + 3 + 1 \text{ (carried over)} = 6$ tens.
• Total blocks: $6$ tens and $1$ one = $61$ blocks.

To add $36 + 47$:

1. Add the ones: $6 + 7 = 13$ ones. Write $3$ in the ones column and carry over $1$ to the tens column.
2. Add the tens: $3 + 4 + 1 \text{ (carry)} = 8$ tens.
3. Total sum: $83$.

• $46 + 39 = 85$
• $56 + 19 = 75$
• $36 + 8 = 44$
• $30 + 58 = 88$
• $45 + 35 = 80$

• Ginladi: To solve $75 - 35$, locate $75$ and count backward $35$ steps to reach $40$.
• Number Line: To solve $19 - 15$, start at $19$, jump backward $10$ steps to $9$, then $5$ steps backward to reach $4$.

• $18 - 9 = 9$
• $12 - 8 = 4$
• $30 - 18 = 12$
• $23 - 14 = 9$
• $26 - 17 = 9$
• $38 - 11 = 27$
• $22 - 22 = 0$ (Subtracting a number from itself results in zero)
• $14 - 0 = 14$ (Subtracting zero leaves the number unchanged)

Jyoti has $46$ flowers ($4$ garlands of $10$ and $6$ loose flowers). She wants to give $18$ flowers to her mother.

• She cannot give $8$ loose flowers from $6$.
• She opens $1$ garland, leaving her with $3$ garlands and $16$ loose flowers.
• Now she subtracts: $16 - 8 = 8$ loose flowers, and $3 - 1 = 2$ garlands.
• Flowers left: $28$.

• $45 - 18 = 27$
• $84 - 37 = 47$
• $65 - 45 = 20$
• $93 - 48 = 45$

A fact family shows how three numbers are related through addition and subtraction:

• Family of $20, 30, 50$:
  $20 + 30 = 50$
  $30 + 20 = 50$
  $50 - 30 = 20$
  $50 - 20 = 30$

• Addition Pyramid: The number in each block is the sum of the two blocks directly below it.
• Subtraction Pyramid: The number in each block is the difference of the blocks below it.