Let's break down each expression and solve them one by one.

Expression D:

$9 + 3 - 5$ First, calculate: $9 + 3 = 12$ Then: $12 - 5 = 7$ The value of Expression D is 7.

Expression E:

$55 \div 11 + 3$ First, divide: $55 \div 11 = 5$ Then: $5 + 3 = 8$ The value of Expression E is 8.

Expression F:

$2 + 9 - 3$ First, calculate: $2 + 9 = 11$ Then: $11 - 3 = 8$ The value of Expression F is 8.

Expression G:

$5 \times 3 - 12 = 3$ First, calculate: $5 \times 3 = 15$ Then: $15 - 12 = 3$ The value of Expression G is 3.

Mapping Numbers to Letters:

Based on the code key provided:

• G = 7
• L = 8
• O = 8

Now, we unscramble the letters G, L, and O.

The correct word is LOG.

This is the code to unlock the lock.

Would you like a deeper explanation, or do you have any questions?

Here are 5 related questions for further practice:

1. What is the value of $7 \times 6 - 4 + 3$?
2. Solve $30 \div 5 + 7 - 2$.
3. If you had to solve $10 + 8 - 6$, what is the answer?
4. Calculate $12 \div 4 + 3 \times 2$.
5. How do parentheses affect the order of operations in expressions?

Tip: Always follow the order of operations (PEMDAS) to avoid mistakes when solving expressions.