Question

Explain how you can use absolute value to tell whether

the sum of two integers is positive or negative.

Answer 1

Explanation:

Let the numbers be x and y

If both are of same signs then

|x + y| = x + y

-|x + y| = -(x + y) = -x - y

If one is negative and one is positive

-|x + (-y)| = -|x - y| = -x + y

-|y + (-x)| = -|y - x| = -y + x

Answer 2

Let the integers are p and q.

In case both integers are positive or negative, you add the numbers up and apply their sign to the sum.

Examples:

• 10 + 88 = 98
• -20 + (-15) = -35

In case one of the integers is negative and one positive.

• p < 0, q > 0

Use absolute value in this case.

Subtract the numbers and apply the sign of the number with the greater absolute value.

Examples:

• - 10 + 15 = |15 - 10| = |5| = 5
• - 15 + 10 = - |15 - 10| = - |5| = -5