The image contains a set of math problems under the heading Section 2.1 Exercises with instructions to round answers to the nearest cent if money is involved. The problems need to be solved using the BEDMAS method (Brackets, Exponents, Division/Multiplication, Addition/Subtraction).

Let's solve them step by step:

1. $81 - 27 + 3 \times 4$

   • Multiply first: $3 \times 4 = 12$
   • Then proceed with addition and subtraction: $81 - 27 + 12 = 66$

2. $100 \div (5 \times 4 - 5 \times 2)$

   • Solve inside the brackets:
     • $5 \times 4 = 20$
     • $5 \times 2 = 10$
     • Now subtract: $20 - 10 = 10$
   • Now divide: $100 \div 10 = 10$

3. $3^1 - 9 + (1 + 7 \times 3)$

   • Solve the exponent: $3^1 = 3$
   • Inside the brackets:
     • Multiply: $7 \times 3 = 21$
     • Add: $1 + 21 = 22$
   • Now calculate: $3 - 9 + 22 = 16$

4. $(6 + 3)^2 - 17 \times 3 + 70$

   • Inside the brackets: $6 + 3 = 9$
   • Solve the exponent: $9^2 = 81$
   • Multiply: $17 \times 3 = 51$
   • Now calculate: $81 - 51 + 70 = 100$

5. $100 - (4^2 + 3) - (3 + 9 \times 3 - 4)$

   • Inside the first set of brackets:
     • Exponent: $4^2 = 16$
     • Add: $16 + 3 = 19$
   • Inside the second set of brackets:
     • Multiply: $9 \times 3 = 27$
     • Now calculate: $3 + 27 - 4 = 26$
   • Now calculate: $100 - 19 - 26 = 55$

The final answers are:

1. $66$
2. $10$
3. $16$
4. $100$
5. $55$

Would you like more details or have any questions? Here are some related questions:

1. Can you apply BEDMAS to more complex expressions with nested brackets?
2. What happens if you perform operations out of order (ignoring BEDMAS)?
3. How do negative exponents change calculations in BEDMAS?
4. How does BEDMAS handle equations with variables?
5. Can BEDMAS be applied to expressions with fractions and decimals?

Tip: Always resolve the innermost brackets first to avoid calculation errors!