Step by step
The question
Question: write 9.99 × 10⁻⁶ as a normal number.
9.99 × 10−6
1 Read the power
10⁻⁶ is 1/1000000.
That divides by 1000000: the number gets smaller, so the point moves 6 places to the left.
10−6 = 11000000
left 6 places
2 Move the point
There are no digits in front of it.
We write 6 zeros in front.
Zeros there do not change the number.
= 0000009.99
A 0 goes in front of the point.
So 9.99 × 10⁻⁶ = 0.00000999.
= 0.00000999
Careful!
The power is not the number of zeros after the point.
It is how many places the point moves.
Careful: not 0.000000999 ✗
3 Check
Let's check: divide by 1000000.
9.99 divided by 1000000 is 0.00000999.
It works!
9.99 ÷ 1000000 = 0.00000999
Let's look back.
First: read the power.
Then: move the point.
Last: check.
Answer
= 0.00000999