The correct answer is B.
Before you start using the number line, you must always keep in mind that:
– and – = +
+ and – = –
+ and + = +
– and + = –
To remember all this you'd also have to keep in mind that all like-terms which are the (– and –) and (+ and +) are both positive or (+). Also, the terms which are not alike such as (– and +) and (+ and –) are negative or (–).
In this problem, we have 2 signs which are (+ and –). As I said above, these terms that are not alike are (–).
On the number line since they're negative, we have to move to the left or subtract. For the opposite of that, we'll have to move to the right or add.
18 + (-18)=0.
To prove this, REMOVE THE BRACKETS and calculate as usual.
18 + - 18 = 0
In this case, we have to SUBTRACT or MOVE TO THE LEFT ON THE NUMBER LINE.
So, the answer is 0 after we subtracted both terms. We do this by:
18 - 18 = 0.
So, we have to:
BEGIN WITH 18 AND MOVE 18 UNITS TO THE LEFT.
Therefore, the answer is B.
