To make the expression easiest to add, you should focus on grouping the terms in a way that simplifies the arithmetic.
Let's analyze the options:
-
Grouping the first expression "18 − 9 + − 8":
- If we calculate it step by step, we can see it as: \[ 18 - 9 - 8 = 1 \] So if we simplify this together with \(4\), \(7\), and the \(9\)s, it won't make the addition easier.
-
Grouping "(18 − 8 − 9)":
- This simplifies to: \[ 18 - 8 - 9 = 1 \] Bringing us back to the same starting point.
-
Grouping "(8 − 18) + ( + )4":
- This option is less straightforward and doesn't lead to a clear addition.
-
Grouping "(18 − 9 − 8) + (− + )4":
- This reduces to: \[ 18 - 9 - 8 = 1 \] Again returning to a similar sum.
-
Grouping "(18 − 8) + (−9 + )4":
- Evaluating this: \[ 18 - 8 = 10 \] And we'd grow complex with the negative which may confuse the addition further.
Recommended Grouping:
The first option of simplifying "(18 - 9 - 8)" typically leads to the easiest calculation.
Thus:
- The expression with the simplest sum is:
- (18 - 9 - 8) + 4 + 7 + 9 + 9
- Which simplifies to 1 + 4 + 7 + 9 + 9 = 30.
This grouping makes the math straightforward and you can calculate it quickly.