The problem consists of five sub-problems related to standard form. 1. Express 450,000 in standard form.

1. Problem Description

The problem consists of five sub-problems related to standard form.

1. Express 450,000 in standard form.

2. Write 0.000072 in standard form.

3. Convert $3.6 \times 10^4$ to an ordinary number.

4. Simplify $2 \times 10^3 \times 4 \times 10^5$ and give your answer in standard form.

5. Subtract $7.8 \times 10^5 - 3.2 \times 10^5$ and give the result in standard form.

2. Solution Steps

1. Express 450,000 in standard form.

To write a number in standard form, we express it as $a \times 10^n$, where $1 \leq a < 10$ and $n$ is an integer.

$450,000 = 4.5 \times 100,000 = 4.5 \times 10^5$

2. Write 0.000072 in standard form.

$0.000072 = 7.2 \times 0.00001 = 7.2 \times 10^{-5}$

3. Convert $3.6 \times 10^4$ to an ordinary number.

$3.6 \times 10^4 = 3.6 \times 10,000 = 36,000$

4. Simplify $2 \times 10^3 \times 4 \times 10^5$ and give your answer in standard form.

$2 \times 10^3 \times 4 \times 10^5 = (2 \times 4) \times (10^3 \times 10^5) = 8 \times 10^{3+5} = 8 \times 10^8$

5. Subtract $7.8 \times 10^5 - 3.2 \times 10^5$ and give the result in standard form.

$7.8 \times 10^5 - 3.2 \times 10^5 = (7.8 - 3.2) \times 10^5 = 4.6 \times 10^5$

3. Final Answer

1. $4.5 \times 10^5$

2. $7.2 \times 10^{-5}$

3. 36,000

4. $8 \times 10^8$

5. $4.6 \times 10^5$