Solve Decimal Multiplication: 0.1 × 0.999 Step by Step

To solve $0.1 \times 0.999$, we need to follow these steps carefully:

• Step 1: Treat the numbers as integers and multiply them. Ignoring the decimal points temporarily, multiply $1$ by $999$:
  $\quad 1 \times 999 = 999$.
• Step 2: Determine the total number of decimal places in the factors.
  $\quad 0.1$ has 1 decimal place.
  $\quad 0.999$ has 3 decimal places.
  Therefore, the product should have $1 + 3 = 4$ decimal places.
• Step 3: Position the decimal in the product calculated in step 1.
  $\quad 999$ with 4 decimal places becomes $0.0999$.

Therefore, the product of $0.1 \times 0.999$ is $0.0999$.