When we add a positive number, we move to the right on a number line. When we add a negative number, we move to the left on the number line.
- 3
We want to determine the total score for the nine holes of golf. Let's start by looking at the scores in the given table!
Hole
1
2
3
4
5
6
7
8
9
Score
+1
- 2
- 1
0
- 1
+3
- 1
- 3
+1
Looking at the table, we can see that some scores are positiveintegers and some scores are negative integers. Let's add up the scores. We can start by adding +1 and -2 on a number line. First, draw an arrow from 0 to 1.
Now we add -2. Recall that when we add a negative number, we move to the left on the number line. Let's draw an arrow 2 units to the left of +1 to represent adding -2!
Notice that for negative integers, the length of the arrow is the absolute value of the number we want to add. Next, let's draw an arrow 1 unit further to the left to represent adding - 1. Then we will add 0 to the sum.
Looking at the diagram, we can see that the sum of the first four holes is - 2. Notice that we cannot see the arrow that represents adding 0 because the addition of 0 to a real number has no effect on the value of the number — the arrow starts and ends at - 2. Now let's add the remaining scores to the sum.
The last arrow ends at - 3. This means that the total score, relative to par, is - 3.
