Solve the Decimal Subtraction: 12.3 - 5.4

Video Solution

Solution Steps

00:04 Let's solve this problem together.

00:07 We'll use long subtraction to find the answer.

00:12 Don't forget, place the decimal point correctly.

00:16 Notice if a digit is smaller than the one you're subtracting from.

00:21 If it is, we need to borrow from the next digit.

00:26 The larger digit decreases by one, and our digit increases by ten.

00:32 Subtract from the larger number and place it in the answer. Like this!

00:40 If the digit is still smaller, we borrow again.

00:44 Use the same method: borrow and subtract.

00:52 Keep subtracting. Remember to place each result correctly.

01:03 Continue this process until you finish all the digits.

01:11 And there you have it! That's the solution.

Step-by-Step Solution

To solve this problem, we will perform the subtraction of two decimal numbers: $12.3$ and $5.4$ .

Here are the steps to follow:

Align the decimals: Write the numbers $12.3$ and $5.4$ vertically with their decimal points aligned.
Subtract the numbers digit by digit: Start from the rightmost digit (tenths place).
$\phantom{x} \, \, 12.3$
$- \, \, \, 5.4$
$\rule{1cm}{0.4pt}$
From the tenths place, $3 - 4$ requires borrowing. Borrow $1$ from the units place of the top number, turning $12.3$ into $12.2$ and making the tenths digit $3+10=13$ . Subtract: $13 - 4 = 9$ .
In the units place, $2 - 5$ needs borrowing as well. Borrow from the tens place: change $12$ into $11$ and $2$ becomes $12$ . Then subtract: $12 - 5 = 7$ .
Since no borrowing is needed in the tens place, retain $1$ as is.
Therefore, the final result is $6.9$ .

Thus, the result of $12.3 - 5.4$ is $6.9$ .