Lesson video

In this lesson, we're going to be looking at dividing numbers that are written in standard form.

If we're dividing six times 10 to the power of five by two, we can rewrite this as six divided by two times 10 to the power of five.

This gives us three times 10 to the power of five.

If we are dividing two numbers that are in standard form, we can rewrite them in the same way.

Eight times 10 to the power of seven, divided by four times 10 to the power of two can be rewritten as eight divided by four, times 10 to the power of seven, divided by 10 to the power of two.

Eight divided by four is two.

10 to power of seven divided by 10 to the power of two, simplifies to 10 to the power of five, because when two numbers have the same base, we just subtract the powers.

As this is in correct standard form, it is our final answer.

In our next example, we've got a decimal and a negative power, but that isn't going to change the method.

We can rewrite this calculation as 9.

6 divided by three, multiplied by 10 to the power of negative two, divided by 10 to the power of four.

9.

6 divided by three is 3.

2.

10 to the power of negative two, divided by 10 to the power of four simplifies to 10 to the power of negative six.

Because this is in correct standard form, it is our final answer.

Here is some questions for you to try, pause the video to complete your task and resume once you're finished.

Here are the answers.

The only power that is changed in all three of these questions is in Part C.

Here are some questions for you to try.

Pause the video to complete your task and resume once you're finished.

Here are the answers.

Make sure that your answers are written in correct standard form.

Here are some questions for you to try.

Pause the video to complete your task and resume once you're finished.

Here are the answers.

In question four, you needed to calculate 750 divided by six times 10 to the power of negative five.

This can be rewritten as 7.

5 times 10 to the power of two, divided by six times 10 to the power of five.

This gives an answer of 1.

25 times 10 to the power of seven.

In question five, you needed to use the fact that one kilogramme is equal to 1000 grammes.

This means the calculation that you're doing is 1000 divided by 2.

5 times 10 to the power of negative two.

This gives an answer of four times 10 to the power four.

Here is a question for you to try.

Pause the video to complete your task and resume once you're finished.

Here is the answer.

The first thing you need to do in this question was work out the approximate amount of the earth that is covered by land.

To write this out, you needed to do 5.

1 times 10 to the power of eight, subtract 3.

6 times 10 to the power of eight.

This gives an answer of 1.

5 times 10 to the power of eight.

To then find the approximate percentage of the Earth's surface covered by land, you needed to do 1.

5 times 10 to the power of eight, divided by 5.

1 times 10 to the power of eight, and then multiply this by 100.

This gives an answer of 29.

41, which we have rounded to 30%.

That's all for this lesson.

Thanks for watching.