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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