The problem presents the stock market's changes over five days, and we are asked to calculate the net change.

Here are the daily changes:

• Day 1: +9.8
• Day 2: -3.5
• Day 3: +20.5
• Day 4: +8.6
• Day 5: -7.7

The overall net change can be found by summing these values:

$\text{Net Change} = 9.8 + (-3.5) + 20.5 + 8.6 + (-7.7)$

I'll calculate the total sum.The overall net change in the market over the five days is +27.7.

Would you like further details or have any questions?

Here are five related questions:

1. What would the net change be if the second day had a different value, say -4.5?
2. How would the net change be affected if the last day had no loss (i.e., 0)?
3. If the stock market continued to change for two more days with values +5.0 and -3.2, what would the new net change be?
4. How can you determine the average daily change over the five days?
5. What would happen to the net change if every day's result was increased by 2 units?

Tip: When dealing with stock market changes, summing the gains and losses over multiple days gives you the net outcome, whether a profit or a loss.