How to calculate 21 minus 30 using long subtraction

How to calculate 21 minus 30

Here we will show you step-by-step how to calculate 21 minus 30 using the long subtraction method.

Before we continue, note that 21 is called the minuend and 30 is called the subtrahend.

To solve the problem 21 minus 30 using long subtraction, we first put the largest number on top and the smallest number at the bottom like this:

	3	0
-	2	1

Then you subtract the ones digits. In this case, the subtrahend ones digit is larger than the minuend ones digit. Therefore, you have to "borrow" 10 from the minuend tens digit, which gives you 10 + 0 - 1 = 9

	2	10
	3	0
-	2	1
		9

Next you subtract the subtrahend tens digit from the new minuend tens digit. 2 - 2 = 0

	2	10
	3	0
-	2	1
	0	9

Note that since the minuend is smaller than the subtrahend, the answer is a negative number.

And that's it. The problem with the answer is displayed below:

21 - 30 = -9

Long Subtraction Calculator
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