Solve: (0.1)(0.15)(3)(0.05) - Decimal Number Multiplication

When you multiply several numbers less than 1, the product gets smaller and smaller! Each decimal multiplication makes the result tinier, which is why $0.1 \times 0.15 \times 3 \times 0.05 = 0.00225$.

Count decimal places in all original numbers before you start: 0.1 has 1, 0.15 has 2, 3 has 0, and 0.05 has 2. Total = 5 decimal places in your final answer.

Yes! Multiplication is commutative, so you can rearrange: $3 \times 0.1 = 0.3$, then $0.3 \times 0.15 = 0.045$, then $0.045 \times 0.05 = 0.00225$.

Try converting to fractions first: $\frac{1}{10} \times \frac{15}{100} \times \frac{3}{1} \times \frac{5}{100}$. Multiply numerators and denominators separately, then convert back to decimal.

Use estimation! $0.1 \times 0.2 \times 3 \times 0.05 ≈ 0.003$, so 0.00225 makes sense. You can also use a calculator to verify your hand calculation.