Question: Homework 1.3: Subtraction of Rational Numbers
Score: 0.5/10 Answered: 0/10
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Question 1
0.5/1 pt 100 98 Details
Suppose you want to subtract: $9 - 12$.
Re-write this subtraction as an ADDITION of signed numbers.
$9 - 12 =$
Now actually compute $9 - 12 =$
1. **State the problem:** We want to subtract $9 - 12$ and rewrite it as an addition of signed numbers.
2. **Rewrite subtraction as addition:** Subtraction of a number is the same as adding its opposite. So,
$$9 - 12 = 9 + (-12)$$
3. **Compute the addition:** Now add $9$ and $-12$.
$$9 + (-12) = \cancel{9} + (-\cancel{9} - 3) = -3$$
Explanation: Adding a negative number means moving left on the number line. Since $12$ is larger than $9$, the result is negative.
4. **Final answer:**
$$9 - 12 = -3$$