# Video: Expressing Numbers in Scientific Notation

There are approximately 200 million cows in India. Express this number in scientific notation.

02:07

### Video Transcript

There are approximately 200 million cows in India. Express this number in scientific notation.

Let’s firstly consider how we would write the number 200 million. The number one million is written as a one followed by six zeros. This means that 200 million can be written as 200 followed by another six zeros. Altogether, we have two followed by eight zeros. A number is written in scientific notation if it is written in the form 𝑎 multiplied by 10 to the power of 𝑏. The absolute value, or modulus, of 𝑎 must be less than 10 and greater than or equal to one. The value of 𝑏 can be a positive or negative integer.

In order to write a number in scientific notation, we firstly put a decimal point after the first nonzero digit. In this question, this is the first digit, two. As the digit after this is a zero, our value for 𝑎 will be 2.0, or just two. In order to find the value of the exponent 𝑏, we need to work out what we multiply two by to give us 200000000. We can do this using place value or by counting how many times the decimal point moves till it gets to the end of our number.

In this question, there are eight bounces, or eight place values. This means that our exponent is eight. As already mentioned, 2.0 is the same as two. So, the number 200 million in scientific notation is two multiplied by 10 to the power of eight. This is approximately the number of cows in India.