Question

Charlie is evaluating the product of 0.09 and 0.05. He multiplies, and before placing the decimal, arrives at an answer of 45. After considering the decimal placement, what is Charlie’s final answer?
0.0045
0.045
0.45
0.4545

Answer 1

To determine Charlie's final answer for the product of 0.09 and 0.05, we first need to calculate the product without considering the decimal points.

When Charlie multiplies 0.09 by 0.05, he treats them as whole numbers first:

0.09 can be expressed as 9 (after removing the decimal place, which is effectively multiplying by 100).
0.05 can be expressed as 5 (after removing the decimal place, which is effectively multiplying by 100).

Thus, he computes:
\[ 9 \times 5 = 45. \]

Now, we need to account for the decimal places.

- 0.09 has 2 decimal places.
- 0.05 has 2 decimal places.

In total, we have \(2 + 2 = 4\) decimal places that need to be placed in the product.

So, we take the result of 45 and place the decimal 4 places from the right:
\[ 45 = 0.0045. \]

Thus, Charlie’s final answer is:
\[ \boxed{0.0045}. \]