There are 2 conditions to remember when adding integers:

1. When adding integers having the same sign, add the numbers and then copy the sign.

–14 and –17 are both negative integers.

14 + 17 = 31

Copy the negative sign.

The sum is –31.

23 and 19 are both positive integers.

23 + 19 = 42

The sum is 42.

2. When adding two integers having different signs, subtract the numbers and copy the sign of the integer with the larger number.

4 is a positive integer and –7 is a negative integer.

Since both integers have different signs, subtract the numbers: 7 – 4 = 3

Since 7 is greater than 4, copy the sign of the integer with 7.

The sum is –3.

Additive inverse of a number is the number that when added to that number will yield zero. It can also be defined as the opposite of a number.

Think about a number that when added to 4 will give us 0.

That number is the negative of 4.

4 + (-4) = 0

So, the additive inverse of 4 is - 4.

First we write the additive inverse of 77, which is -77.

Then we think about the number that when added to -77 will yield 55.

Mathematically,

-77 + ? = 55

- 77 + 22 = 55

First we add the integers without the minus sign.

80 + 40 = 120

Now, we put the minus sign.

So, (-80)- 40 = - 120

(-200) - (-572)

= - 200 + 572

When we subtract the integers, we get 372.

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