Indira is using a number line to add Negative 1 + (negative 3). She begins by showing –1 on the number line, as shown below.

Question

A number line going from negative 5 to positive 5. The area between negative 1 and 0 is highlighted.

What is the sum of Negative 1 + (negative 3)?
–4
–3
2
3

Answer 1

To solve the problem, we start with \(-1\) on the number line and then add \(-3\).

1. Start at \(-1\).
2. To add \(-3\), we move 3 units to the left on the number line because we are adding a negative number.

Starting at \(-1\):

• Move 1 unit left to \(-2\)
• Move another unit left to \(-3\)
• Move one more unit left to \(-4\)

After moving 3 units left from \(-1\), we end up at \(-4\).

Thus, the sum of \(-1 + (-3)\) is \(-4\).

The correct answer is: \(-4\)