Final answer:
To rewrite -3 + [-4] as a subtraction problem using a number line, you start at -3 and move 4 units left, reaching -7, which is equivalent to -3 - (+4). The correct approach is: B) By starting at -3 and moving 4 units to the left to reach the result
Step-by-step explanation:
To use a number line to rewrite -3 + [-4] as a subtraction, we need to understand how the addition and subtraction of integers work. When we add two negative numbers, like -3 and [-4], we move left on the number line because we are adding more negative values. Therefore, the correct approach is: B) By starting at -3 and moving 4 units to the left to reach the result.
This is analogous to the subtraction of scalars; to perform the subtraction, we change the sign of the number being subtracted and then follow the rules for addition. So, if we were to rewrite -3 + [-4] as a subtraction problem, it would become -3 - (+4), which is the same as starting at -3 on the number line and moving 4 units to the left. This technique is similar to vector subtraction, where subtracting a vector is the same as adding its negative. For example, A - B is equivalent to A + (-B). This gives us the same result regardless of the order in which we perform the addition or subtraction. In the number line method, each unit moving to the left indicates subtracting one unit, thus moving from -3 to -7 while subtracting 4 units or adding [-4].