# What is 0.0000004 in scientific notation?

Nov 9, 2016

$4 \times {10}^{-} 7$

#### Explanation:

You need one digit before the decimal point and then a power of 10.

The decimal is formed by dividing by 10 seven times. The index will be negative.

$4 \times {10}^{-} 7$

Probably too late for the quiz, but you can learn it now for next time . EZ

Nov 9, 2016

$0.000 000 4 = 4 \times {10}^{-} 7$

#### Explanation:

$0.000 000 4 = 4 \times {10}^{-} 7$

You have to move the decimal point until it is on the right side of the 4, to give $4.0$ Count how many places the decimal point moved..

As fractions: $0.4 = \frac{4}{10} = 4 \times {10}^{-} 1 \text{ } \leftarrow$ one decimal place

$0.04 = \frac{4}{100} = \frac{4}{10} ^ 2 = 4 \times {10}^{-} 2 \text{ } \leftarrow$ 2 decimal places

$0.004 = \frac{4}{1000} = \frac{4}{10} ^ - 3 \text{ } \leftarrow$ 3 decimal places

and so on until

$0.0000004 = \frac{4}{10000000} = \frac{4}{10} ^ 7$

$\frac{4}{10} ^ 7 = 4 \times {10}^{-} 7 \text{ } \leftarrow$ 7 decimal places