Express the number apperaring in the following statements in standard form.
The universe is estimated to be about `12,000,000,000` years old.

Answer

To express the number `12,000,000,000` in standard form, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the significant digits**: The first significant digit in `12,000,000,000` is `1` followed by `2`. Therefore, we can express this number as `1.2`.

2. **Count the number of places the decimal point moves**: To convert `12,000,000,000` into standard form, we need to move the decimal point from the end of the number (after the last zero) to just after the first significant digit. In this case, we move the decimal point 10 places to the left.

3. **Express the movement of the decimal point in terms of powers of 10**: Since we moved the decimal point 10 places to the left, we can express this as multiplying by `10` raised to the power of `10`.

4. **Combine the significant digits with the power of 10**: Therefore, we can write the number in standard form as:
\[ 1.2 \times 10^{10} \]

### Final Answer:
The age of the universe in standard form is:
\[ 1.2 \times 10^{10} \text{ years old} \]