Question

Find the value \[-15-(-18)\]

Answer 1

Hint:Here, in this problem we have apply the Arithmetic operation that means to approach this problem, we need to use the subtraction rule that is \[(-)-(+)=(-)+(+)\] and put the sign of greater number sign in the final result.

Complete step by step solution:
Before solving this problem, first we need to understand the concept of Arithmetic rule for integers, that is addition, subtraction and multiplication rule. But to approach this type of problem, we need to understand the subtraction rule which is given as:
Subtraction rule: Subtracting means adding the opposite of a given number or changing the signs of the number. The sign of the first number remains the same, change subtraction to addition and change the sign of the second number. Once you have applied this rule, follow the rules for subtracting integers.
Now, we come to the problem,
For solving this particular problem which is given as:
\[\Rightarrow -15-(-18)\]
For this, we need to apply the subtraction rule for integer that is
\[\Rightarrow (-)-(+)=(-)+(+)\]
By applying this rule that is changing the sign and opposite to the number and adding we get:
\[\Rightarrow -15+18\,\] (18 is the opposite of \[-18\])
Then, by consider the greater number sign we get:
\[\Rightarrow +3\] (Here, 18 is greater number than 15 hence, sign is positive)
Therefore, \[-15-(-18)=+3\]
Hence, the correct answer is \[+3\].

Additional information:
Multiplication Rule: To multiply or divide an integer, use the absolute value. If the signs of the integers are the same, multiply, or divide the answer is always positive. And if the two integers have different signs, the answer is negative.
Addition rule: To add two integers with the same sign: If the sign of both the integers is the same, then add the absolute value and the result is assigned the same sign as both the values.


Note:
In this type of problem always remember and take care about the sign which we put on the final result. Because it is easy to remember the sign of the addition and multiplication rule in the final answer. But for the subtraction rule you will have many chances of making the mistake of considering the answer sign for the final answer. You may consider the smaller number sign that makes the answer wrong because, for subtraction, always consider the greater number sign for the final result.