This double digit subtraction worksheet helps students practice subtracting two-digit numbers without regrouping, using visual base-10 block representations to build understanding.

Problem Analysis:

The task involves solving double-digit subtraction problems without regrouping. This means that in each subtraction problem, the digit in the ones place of the minuend (the number being subtracted from) is greater than or equal to the digit in the ones place of the subtrahend (the number being subtracted). Similarly, the digit in the tens place of the minuend is greater than or equal to the digit in the tens place of the subtrahend.

We are also asked to represent the solutions using a visual model, likely base-10 blocks, where:
- A long bar represents 10 units.
- A small square represents 1 unit.

Step-by-Step Solution:

#### 1. 49 - 31 = 18
- Minuend: 49 (4 tens and 9 ones)
- Subtrahend: 31 (3 tens and 1 one)
- Subtract the ones: \( 9 - 1 = 8 \)
- Subtract the tens: \( 4 - 3 = 1 \)
- Result: \( 18 \)

Visual Representation:
- Start with 4 tens and 9 ones.
- Remove 3 tens and 1 one.
- Remaining: 1 ten and 8 ones.

#### 2. 56 - 44 = 12
- Minuend: 56 (5 tens and 6 ones)
- Subtrahend: 44 (4 tens and 4 ones)
- Subtract the ones: \( 6 - 4 = 2 \)
- Subtract the tens: \( 5 - 4 = 1 \)
- Result: \( 12 \)

Visual Representation:
- Start with 5 tens and 6 ones.
- Remove 4 tens and 4 ones.
- Remaining: 1 ten and 2 ones.

#### 3. 46 - 21 = 25
- Minuend: 46 (4 tens and 6 ones)
- Subtrahend: 21 (2 tens and 1 one)
- Subtract the ones: \( 6 - 1 = 5 \)
- Subtract the tens: \( 4 - 2 = 2 \)
- Result: \( 25 \)

Visual Representation:
- Start with 4 tens and 6 ones.
- Remove 2 tens and 1 one.
- Remaining: 2 tens and 5 ones.

#### 4. 61 - 10 = 51
- Minuend: 61 (6 tens and 1 one)
- Subtrahend: 10 (1 ten and 0 ones)
- Subtract the ones: \( 1 - 0 = 1 \)
- Subtract the tens: \( 6 - 1 = 5 \)
- Result: \( 51 \)

Visual Representation:
- Start with 6 tens and 1 one.
- Remove 1 ten and 0 ones.
- Remaining: 5 tens and 1 one.

#### 5. 78 - 38 = 40
- Minuend: 78 (7 tens and 8 ones)
- Subtrahend: 38 (3 tens and 8 ones)
- Subtract the ones: \( 8 - 8 = 0 \)
- Subtract the tens: \( 7 - 3 = 4 \)
- Result: \( 40 \)

Visual Representation:
- Start with 7 tens and 8 ones.
- Remove 3 tens and 8 ones.
- Remaining: 4 tens and 0 ones.

#### 6. 44 - 33 = 11
- Minuend: 44 (4 tens and 4 ones)
- Subtrahend: 33 (3 tens and 3 ones)
- Subtract the ones: \( 4 - 3 = 1 \)
- Subtract the tens: \( 4 - 3 = 1 \)
- Result: \( 11 \)

Visual Representation:
- Start with 4 tens and 4 ones.
- Remove 3 tens and 3 ones.
- Remaining: 1 ten and 1 one.

Final Answers:

\[
\begin{aligned}
&49 - 31 = 18 \\
&56 - 44 = 12 \\
&46 - 21 = 25 \\
&61 - 10 = 51 \\
&78 - 38 = 40 \\
&44 - 33 = 11 \\
\end{aligned}
\]

Boxed Final Answer:

\[
\boxed{18, 12, 25, 51, 40, 11}
\]