Here is the solution for the given problems from the image:

(9) $588 + 546$
Step-by-step:

• $8 + 6 = 14$, write down $4$, carry over $1$.
• $8 + 4 + 1 = 13$, write down $3$, carry over $1$.
• $5 + 5 + 1 = 11$.

Final Answer: 1134

(10) $128 + 972$
Step-by-step:

• $8 + 2 = 10$, write down $0$, carry over $1$.
• $2 + 7 + 1 = 10$, write down $0$, carry over $1$.
• $1 + 9 + 1 = 11$.

Final Answer: 1100

(11) $168 + 835$
Step-by-step:

• $8 + 5 = 13$, write down $3$, carry over $1$.
• $6 + 3 + 1 = 10$, write down $0$, carry over $1$.
• $1 + 8 + 1 = 10$.

Final Answer: 1003

(12) $260 + 437$
Step-by-step:

• $0 + 7 = 7$.
• $6 + 3 = 9$.
• $2 + 4 = 6$.

Final Answer: 697

(13) $12 + \_\_\_ = 34$
Missing value: $34 - 12 = 22$.

Final Answer: 22

(14) $24 + \_\_\_ = 67$
Missing value: $67 - 24 = 43$.

Final Answer: 43

(15) $21 + \_\_\_ = 75$
Missing value: $75 - 21 = 54$.

Final Answer: 54

(16) $546 + 340$
Step-by-step:

• $6 + 0 = 6$.
• $4 + 4 = 8$.
• $5 + 3 = 8$.

Final Answer: 886

Let me know if you'd like additional details on any of these solutions or further explanations!

Related Questions:

1. What strategies can you use to check the accuracy of addition problems?
2. How does carrying over digits work in multi-digit addition?
3. Can you solve $345 + 768$ and explain your reasoning step-by-step?
4. How would you solve subtraction problems like $845 - 437$?
5. What are some tricks for mentally calculating sums?

Tip:

When solving addition problems, align the numbers by their place values (ones, tens, hundreds) to ensure accuracy!