Solve the Decimal Subtraction: 12.3 - 5.4

Video Solution

Solution Steps

00:00 Solve

00:03 We'll use long subtraction for calculation

00:08 We'll place the decimal point in the appropriate position

00:11 The digit is smaller than the digit we need to subtract from

00:14 Therefore, we'll borrow from the next digit

00:18 The larger digit will decrease by 1, and our digit will increase by 10

00:22 Now we'll subtract from the larger number, and place

00:36 Again, the digit is smaller than the digit we need to subtract from

00:40 Therefore, we'll use the same method and borrow from the next digit

00:48 Now we'll subtract from the larger number, and place

00:59 We'll continue to subtract and place accordingly

01:07 And this is the solution to the problem

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 $6.9$ .