Question

ms. ordonez/ms. sparacello/ ms. brea
add or subtract? (do not evaluate)

1. (-10)+(10)
2. (-13)+(-5)
3. 8+(-15)
4. - 9+(7)
5. - 6+(-23)
6. 19+(-20)

change these subtraction expressions to addition expressions.

1. 7-(-11)
2. (-18)-14
3. (-13)-(-5)
4. -17 - 1
5. 2 - 4

Explanation:

Step1: Recall subtraction - addition rule

Subtracting a number is the same as adding its additive inverse. That is, $a - b=a+( - b)$.

Step2: Rewrite first expression

For $7-(-11)$, the additive inverse of $- 11$ is $11$. So it becomes $7 + 11$.

Step3: Rewrite second expression

For $(-18)-14$, the additive inverse of $14$ is $-14$. So it becomes $(-18)+(-14)$.

Step4: Rewrite third expression

For $(-13)-(-5)$, the additive inverse of $-5$ is $5$. So it becomes $(-13)+5$.

Step5: Rewrite fourth expression

For $-17 - 1$, the additive inverse of $1$ is $-1$. So it becomes $-17+(-1)$.

Step6: Rewrite fifth expression

For $2 - 4$, the additive inverse of $4$ is $-4$. So it becomes $2+(-4)$.

Answer:

1. $7 + 11$
2. $(-18)+(-14)$
3. $(-13)+5$
4. $-17+(-1)$
5. $2+(-4)$