Create a blackboard plan for subtracting two-digit numbers, including examples with and without borrowing, and visual aids for explanation.

Here is a sample blackboard plan with descriptions of the pictures, based on the image you sent:

Blackboard Plan: Subtracting Two-Digit Numbers (with Borrowing)

1. Let's Subtract Vertically!

• Problem: $74 - 32$
• Calculation: $$\begin{array}{c} 74 \\ -32 \\ \hline 42 \\ \end{array}$$

2. How to Subtract $45 - 27$ (Using Vertical Form)

• Problem: $$\begin{array}{c} 45 \\ -27 \\ \hline \end{array}$$
• Step 1: Look at the Ones Place
  • Can we take 7 from 5? No.
  • (Picture: Show 4 tens blocks and 5 single blocks.)
• Step 2: Borrow from the Tens Place
  • Take 1 ten from the 4 tens. Now we have 3 tens.
  • Add 10 ones to the 5 ones. Now we have 15 ones.
  • (Picture: Show 3 tens blocks and 15 single blocks. An arrow shows one ten block changing into ten single blocks.)
• Step 3: Subtract the Ones
  • $15 - 7 = 8$
  • (Picture: Show 3 tens blocks and 15 single blocks, with 7 single blocks crossed out, leaving 8 single blocks.)
• Step 4: Subtract the Tens
  • $3 - 2 = 1$
  • (Picture: Show 3 tens blocks, with 2 tens blocks crossed out, leaving 1 ten block.)
• Final Calculation: $$\begin{array}{c} \phantom{0}\overset{3}{\cancel{4}}\overset{15}{\cancel{5}} \\ -27 \\ \hline \phantom{0}18 \\ \end{array}$$
• The answer is $\boxed{\text{18}}$.

3. Practice These!

• $41 - 19$
• $70 - 36$
• $81 - 48$
• $62 - 24$