Question

How do you round 7.43647616796 to the nearest millionth?

Answer 1

In order to solve this problem, we need to understand what each decimal place is called.

Explanation:

Look at this picture:

As you can see, the first decimal place is 9 tenths, the second is 8 hundredths, the third is 7 thousandths, and so on. The second to last spot, however, is what is important to us. The second to last decimal place is 4 millionths. Notice that the millionths digit is the sixth digit after the decimal point. Let's take a look at our number now:

`7.43647616796`

The sixth number after the decimal point is a `6`. Therefore, let's take off the last four digits in our number, but we're going to keep the `1`, as this is crucial to rounding the number. We now have this:

`7.4364761`

The rule of rounding is this:

If the digit following another digit is 5 or greater, the first digit is "rounded up" and increases by 1.
If the digit following another digit is 4 or less, the first digit doesn't change.

The digit following our millionths digit (`6`) is `1`. As the rule states, `1<5`, so the millionths digit doesn't change. We can now take off the `1`. This is our final answer:

`7.436476`