What is 8 8 4 12

Simplified notation for adding and subtracting

Adding and subtracting a positive Number:


  $$( +5 ) + ( + 9 )$$ $$ =5 + 9 = 14$$
                ↙     ↘
instead of $$ (+ 5) $$ instead of $$ (+ 9) $$
              $$5$$           $$9$$


  $$( +12 ) - ( + 23 )$$ $$ =12 -23 = -11$$
                    ↙     ↘
instead of $$ (+ 12) $$ instead of $$ (+ 23) $$
                  $$12$$           $$23$$

Adding and subtracting a negative Number:


   $$( - 8 ) - ( - 14 ) $$ $$=( - 8 ) + ( + 14 )$$ ↘
Subtracting $$ (- 14) $$
means adding $$ (+14) $$
                 $$ =- 8 + 14 = 6$$
                  ↙
instead of $$ (- 8) $$
             $$-8$$


   $$(- 13 ) - ( + 16 ) = - 13 + ( -16 )$$ ↘
Adding $$ (- 16) $$ means
subtract from $$ (+16) $$
                 $$=- 13$$ $$ – 16 = - 29$$
                  ↙
instead of $$ (- 13) $$
             $$-13$$

Subtracting a number is the same as adding the opposite number

Bracket rules for addition and subtraction

1st example: sign of the bracket "$$ + $$"

Step 1: Release the clamp

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

2nd step: Combine numbers with the same sign

$$12 + 8$$ $$– 4 = 20$$ $$– 4 $$

3rd step: Group numbers according to the sign rules

$$20$$ $$– 4 = 16$$

A “$$ + $$” in front of the brackets means that the signs do not change when the brackets are broken!

2nd example: sign of the bracket "$$ - $$"

Step 1: Release the clamp

$$28 - ( 6 + 4 ) = 28$$ $$– 6 - 4 $$

2nd step: Combine numbers with the same sign

$$28$$ $$– 6$$ $$– 4 = 28 - 10$$

3rd step: Group numbers according to the sign rules

$$28$$ $$– 10 = 18$$

A “$$ - $$” in front of the brackets means that the signs change when the brackets are broken!

 

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