Question

How do you subtract: a negative number minus a positive number?

Answer 1

Rule 1: Subtracting a positive number from a positive number—this is normal subtraction.

Example 1: Don’t let all this talk of positive and negative numbers throw you off track—if you see a positive number minus a positive number, subtract it like normal! For example, if you see 5 – 3, subtract normally! 5 – 3 = 2.

Rule 2: Subtracting a positive number from a negative number—start at the negative number, and count backwards the additional amount you’re subtracting.

Example 2: Let’s say we had the problem -5 – 3. This would be read as “negative five minus three.” This can be thought of on a number line, which means we’re going to start at the negative number (-5) and keep counting back the -3, arriving at -8, like this:



The large red dot above the -5 shows that that’s where we’re starting our problem. The red arrow shows that we counted backwards (subtracted) 3. The red circle around the –8 shows that that’s our answer.

Thus, -5 – 3 = -8.

You can also think about these problems as addition problems—you add the numbers together (5 + 3 = 8) and then, since both numbers have a minus sign in front of them, you would add a negative sign in front of your answer, like this: -8. If this makes more sense, you can do these problems like this—but only problems that are written like this: -5 – 3. If there are any other signs (addition, subtraction, etc) you need to follow the rule for that type of problem.

Rule 3: Subtracting a negative number from a negative number—when you see the subtraction (minus) sign followed by a negative sign, turn the two signs into a plus sign. Thus, instead of subtracting a negative, you are adding a positive. So, – -5 becomes +5, and continue normally with the addition.

Example 3: Let’s say we had the problem -6 – -3. This would be read as “negative six minus negative three.” This can be thought of on a number line, which means we’re going to start at by changing the – -3 into +3, like this:



Now our problem reads -6 + 3, which we can solve as a normal addition problem on the number line, like this:



The large red dot above the -6 shows that that’s where we’re starting our problem. The blue arrow shows that we counted forward (added) 3. The blue circle around the –3 shows that that’s our answer.

Rule 4: Subtracting a negative number from a positive number—when you see the subtraction (minus) sign followed by a negative sign, turn the two signs into a plus sign. Thus, instead of subtracting a negative, you’re adding a positive, so you have a simple addition problem.

Example 4: Let’s say we had the problem 5 – (-3). This would be read as “five minus negative three.” This would work the same way as the previous example, so the – (-3) would change to a +3; therefore, your new problem would read 5 + 3, which is a simple addition problem, resulting in 8.

Subtracting Positive and Negative Numbers Quiz
Problems
1. 4 – 2 2. -8 – 5 3. -4 – (-7) 4. 6 – (-3) 5. -9 – 1
6. -10 – (-8) 7. 9 – 4 8. 2 – (-7) 9. -7 – 8 10. -5 – (-6)

Answer 2

Now first we have a negative number minus positive number
Now take common minus sign from both sides and add the numbers in bracket
So adding the number will positive in bracket so on multiplying by minus the number will be negative

Or
Simply add the numbers and give minus sign to them