Subtract 423–23.5

423 - 23.5 equals 399.5

To subtract 423 - 23.5, follow these steps:

Step 1: Write down the numbers vertically, with the larger number on top and the smaller number on the bottom:

423
-23.5

Step 2: Subtract the numbers in the rightmost column (the ones place):

3 - 5 = -2

Since we cannot subtract a larger number from a smaller number in the ones place, we need to borrow from the tens place.

Step 3: Borrowing from the tens place: Reduce the number in the tens place by 1 (4 becomes 3) and add 10 to the ones place (which is now -2 + 10 = 8).

32
-20.5

Step 4: Subtract the numbers in the rightmost column (the tens place):

3 - 0 = 3

Step 5: Subtract the numbers in the rightmost column (the tenths place):

2 - 5 = -3

Since we cannot subtract a larger number from a smaller number in the tenths place again, we need to borrow from the ones place.

Step 6: Borrowing from the ones place: Reduce the number in the ones place by 1 (3 becomes 2) and add 10 to the tenths place (which is now -3 + 10 = 7).

32
-10.5

Step 7: Subtract the numbers in the rightmost column (the ones place):

2 - 0 = 2

Step 8: Subtract the numbers in the rightmost column (the tenths place):

3 - 5 = -2

Step 9: Subtract the numbers in the rightmost column (the hundredths place):

1 - 0 = 1

Step 10: Combine the results of each column to get the final answer:

423
-23.5
------
379.5

Therefore, 423 - 23.5 = 379.5.