Let's solve the two questions visible in the image:

Question 15:

$532 + 678 + 984 - 357$

1. Add the first three numbers: $532 + 678 = 1210$ $1210 + 984 = 2194$

2. Subtract 357 from 2194: $2194 - 357 = 1837$

So, the answer to 15 is: $1837$

Question 16:

$23.54 - 17.28 + 34.21$

1. Subtract 17.28 from 23.54: $23.54 - 17.28 = 6.26$

2. Add 34.21 to 6.26: $6.26 + 34.21 = 40.47$

So, the answer to 16 is: $40.47$

Would you like more detailed explanations or have any questions? Here are five related questions for practice:

1. What is $850 + 643 - 120$?
2. Simplify $19.45 + 25.34 - 12.56$.
3. Calculate $763 + 912 - 485$.
4. What is $45.67 - 34.12 + 78.23$?
5. Find $123 + 456 + 789 - 321$.

Tip: When dealing with multiple additions and subtractions, always solve step by step to avoid mistakes!