This page extends the addition in first principles into a simplified procedure for addition of integers, which is called *sign property of integer addition*.

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In whole numbers, we had studied the following.**Addition by Place-value with regrouping** -- simplified procedure : Two numbers are added as per the following procedure:

• the place-value positions are arranged units under units, `10`s under `10`s, etc.

• the units are added and if the result has `10` numbers, then it is carried to the `10`s place.

• The addition is continued to the higher place-value position. The carry over is the simplification of combining `10` of a place value to a higher place value.

The terminology "received" and "given" symbolically refer to the positive and negative numbers of all applications.

For example, temperature `3^@` above `0` and `2^@` below `0` are referred as `text(received:)3` and `text(given:)2` respectively. The same in integers is `3` and `-2`.

Integers are directed whole numbers.

`text(received:)3` is also referred as `text(aligned:)3`, meaning the magnitude given by the number is aligned to the chosen direction.

`text(given:)2` is also referred as `text(opposed:)2`, meaning the magnitude given by the number is opposed to the chosen direction.

For example, temperature `3^@` above `0` and `2^@` below `0` are referred as `text(aligned:)3` and `text(opposed:)2` respectively. The same in integers is `3^@C` and `-2^@C`.

`4+3=7`

By first principles, `text(received:)4` and `text(received:)3` together is `text(received:)7`.

`4+(-3) = 1`

By first principles, `text(received:)4` and `text(given:)3` together is `text(received:)1`.

This addition is equivalent to whole number subtraction `4-3=1`.

`4+(-7)= (-3)`

By first principles, `text(received:)4` and `text(given:)7` together is `text(given:)3`.

This addition is equivalent to whole number subtraction `7-4=3`, with the result modified to the sign of larger absolute value.

`(-4) + (-3) = -7`

By first principles, `text(given:)4` and `text(given:)3` together is `text(given:)7`.

This addition is equivalent to whole number addition `4+3=7`, with result modified to the sign of the two addends.

Summary of integer addition illustrative examples:

• `4+3 = 7` : To `text(received:)4` another `text(received:)3` is put-in

• `4+(-3) = 1` : To `text(received:)4` another `text(given:)3` is put-in

• `-4 + 3 = -1` : To `text(given:)4` another `text(received:)3` is put-in

• `4+(-7) = -3` : To `text(received:)4` another `text(given:)7` is put-in

• `-4+(-3) = -7` : To `text(given:)4` another `text(given:)3` is put-in

Based on this, the addition is simplified as**sign-property of addition**

• +ve + +ve is whole number addition of absolute values

• +ve + -ve is subtraction as given below

absolute values of the two numbers are compared

subtract the number of smaller absolute value from the number of larger absolute value. The difference is the absolute value of the result.

the sign of result is the sign of the number with larger absolute value

• -ve + -ve The result is sum of absolute values with negative sign.

The addition or subtraction of absolute values in the procedure are detailed in *addition by place-value* and *subtraction by place-value*.

**Addition of Integers Simplified Procedure** : Two numbers with signs positive or negative are added as follows. **sign-property of addition**

• +ve `+` +ve is whole number addition

• +ve `+` -ve is subtraction as given below

absolute values of the two numbers are compared

subtract the number of smaller absolute value from the number of larger absolute value. The difference is the absolute value of the result.

the sign of result is the sign of the number with larger absolute value

• -ve `+` -ve is addition of absolute values with negative sign.

The addition or subtraction of absolute values in the procedure are detailed in *addition by place-value* and *subtraction by place-value*

*Solved Exercise Problem: *

Find the sum of `-6` and `0`.

- `-6`
- `-6`
- `+6`

The answer is "`-6`"

*Solved Exercise Problem: *

Find the sum of `11` and `-140`

- `-30`
- `-129`
- `-129`

The answer is "`-129`"

*Solved Exercise Problem: *

Find the sum of `2` and `-2`

- `0`
- `0`
- `4`

The answer is "`0`"

*Solved Exercise Problem: *

Find the sum of `-2345` and `-889`

- `-3234`
- `-3234`
- `-1456`

The answer is "`-3234`"

*switch to interactive version*