Question

Maybeline is the teacher's assistant today and is correcting homework examples. Help her by selecting correct or incorrect after evaluating each problem.

Answer 1

Here, we need to remember the signs rules

$\begin{gathered} (+)(+\text{ )=+} \\ (+\text{ )(- )=-} \\ (-\text{ )(+ )=-} \\ (-\text{ )(- )=+} \end{gathered}$

Then

$(-4)+(-8)=-4-8=-12$

incorrect.

$(-9)-(-8)=-9+8=-1$

correct

$(+7)\times(-8)=-56$

correct

$(-5)(-2.5)=12.5$

correct

$+\frac{1}{2}\times(+6)=3$

incorrect