This is very much similar to the two-digit subtraction. You will find, in the end of this page that only the number of digits is more and the rest is all the same.
As we know the concept of place value very well now, let's start off the problem straight away using “without regrouping (borrowing)” method.
Write the two three-digit numbers of the math problem as given below (one on top and the other below), before subtracting.
Now, let's consider the 'ones' place in this subtraction.
4-2=2. Write 2 in the 'ones' column.
Similarly, let's do the same for the numbers in 'tens' column of this math problem.
Subtracting 2 from 4, we get 2. Now, write 2 in the 'tens' column. Now, do the same in 'hundreds' column.
4-1=3. Write 3 in the 'hundreds' column.
We got the answer! Its 322.
Subtracting three-digit numbers without regrouping (borrowing) is made easy here.