Step by step
The question
Question: work out (3 × 10⁴) × (2 × 10⁵).
(3 × 104) × (2 × 105)
1 Group the parts
Times can go in any order.
So we put the numbers together, and the powers of 10 together.
= 3 × 2 × 104 × 105
2 Work out each part
3 times 2 is 6.
3 × 2 = 6
We write 6 for the numbers.
= 6 × 104 × 105
The rule: same base, times, add the powers.
4 plus 5 is 9.
104 × 105 = 104 + 5 = 109
So the answer is 6 × 10⁹.
= 6 × 109
3 Check
Let's check the answer is in scientific notation.
6 is from 1 to under 10, and it is times a power of 10.
Yes!
6 is from 1 to under 10, times 109
Let's look back.
First: group the parts.
Then: work out each part.
Last: check.
Answer
= 6 × 109