Homework Help

how do you calculate the sum of 1-4 and 1-7

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angiescows2 | eNotes Newbie

Posted October 20, 2013 at 9:34 PM via web

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how do you calculate the sum of 1-4 and 1-7

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amysor | Student, Grade 10 | Valedictorian

Posted October 21, 2013 at 12:10 AM (Answer #1)

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I suppose you add the two problems up because of the word sum

`(1-4) + (1-7)`

`-3 + (-5)`

`= -8`

So the sum between 1-4 and 1-7 would be -8.

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mjripalda | High School Teacher | (Level 3) Educator

Posted October 21, 2013 at 12:49 AM (Answer #2)

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To get the sum, put parenthesis around 1-4 and around 1-7 to indicate separate groups. Then, add the two groups.

`(1-4)+(1-7)`

Then, simplify by doing the operation inside each group.

`=-3 + (-6)`

Since the simplified form of the two groups have the same sign, to compute, add the numbers and copy the sign.

`=-9`

Hence, the sum of 1-4 and 1-7 is  -9.

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