We use the numbers line to illustrate the addition of 3 and 4. We start at 0 and proceed three units to the right to 3. We then proceed four more units to the right; this brings us to 7. So 3 + 4 = 7
Now, let us consider the addition of negative numbers, e.g. -2 and -5. To add the negative integers -2 and -5 on the numbers line, we start at 0 and proceed two units to the left to -2. Then we proceed five more units to the left; this brings us to -7, (-2) + (-5) = -7
(-2)+ (-5) = -7
Notice that the sum of two negative integers is the negative of the sum of their numerical values. i.e.
(-2) + (-5) = -2 -5 = -(2+5) = -7
Find the sum of the following:
When subtraction involves a negative number, we should learn some rules. Consider the following examples: subtract -2 from 6 i.e. 6 - (-2) = 8. When two negative signs (-) appear with the same number, it becomes positive. 6 - (-2) = 6 + 2 = 8. So, when subtracting a negative number, the number becomes positive.
Find the result of the following operations: