Subtract Decimals: Finding 5.4 - 0.21 Step by Step

To solve this problem, we will subtract the decimal number $0.21$ from $5.4$ by following these steps:

• Step 1: Align the decimal points in both numbers.

• Step 2: Note that $5.4$ can be written as $5.40$ to facilitate subtraction.

• Step 3: Subtract $0.21$ from $5.40$ by starting from the rightmost decimal place.

Now, let's work through each step:

Step 1: Align the decimals:
$\begin{aligned} 5&.4\\ - ~~0&.21\\ \hline{\phantom{3232}} \end{aligned}$

Step 2: Perform the subtraction, starting from the rightmost digit:

• Subtract the hundredths column: $0 - 1$ requires borrowing.
  From $4$ in the tenths column, reduce it to $3$, making the hundredth column $10$, then $10 - 1 = 9$.

• Subtract the tenths column: $3 - 2 = 1$.

• Subtract the units column: $5 - 0 = 5$.

The result of the subtraction is:
$5.19$

Therefore, the solution to the problem is $5.19$.