Question

Mason owes
$
5
to each of his
4
friends. He represents how much he owes in total on the number line. Mason concludes that he has a debt of
$
20
.



image



Which statement BEST evaluates Mason's representation of the amount he owes?



A.
Mason demonstrated
5
×
(
−
4
)
instead of
(
−
5
)
×
4
on the number line. The interpretation of the product as the amount of debt is correct.

B.
Mason demonstrated
5
×
(
−
4
)
instead of
(
−
5
)
×
(
−
4
)
on the number line. The interpretation of the product as the amount of debt is correct.

C.
Mason demonstrated
5
×
(
−
4
)
instead of
(
−
5
)
×
4
on the number line. The interpretation is incorrect because the product is the amount of money Mason has.

D.
Mason demonstrated
5
×
(
−
4
)
instead of
(
−
5
)
×
(
−
4
)
on the number line. The interpretation is incorrect because the product is the amount of money Mason has.

Answer 1

A.

Both 5 × (−4) and (−5) × 4 equal −20, so Mason’s number-line representation (5 groups of −4 instead of 4 groups of −5) still gives the correct total debt (magnitude 20, negative on the number line).