What is 4 minus negative 81?

Here we will not only give you the answer to 4 minus negative 81, but also explain how we got the answer.

Start by picturing a number line that goes to negative infinity on the left side of 0 and positive infinity on the right side of 0:

∞ ..... -3, -2, -1, 0, +1, +2, +3, .... ∞

Looking at the number line above, we can make the following observation:

Adding a positive number goes to the right.
Adding a negative number goes to the left.

Adding and subtracting cannot go in the same direction on a number line. Therefore, this must also be true:

Subtracting a positive number goes to the left.
Subtracting a negative number goes to the right.

Thus, with the problem 4 minus negative 81, we are subtracting a negative number and we go to the right. Specifically, we go from +4 to +85 on the number line.

Here is 4 minus negative 81 in mathematical terms with the answer:

4 - (-81) = 85

You may already know that minus minus equals plus or that 4 minus negative 81 is the same as 4 plus 81, but we hope that this page explained the underlying mathematical reason for the answer.

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What is 4 minus negative 82?
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