Q: How is the number 40,139,321 written in Scientific Notation?
A: 4.0139321 x 107
The purpose of scientific notation is for scientists to write very large, or very small, numbers with ease.
Calculating scientific notation for a positive integer is simple, as it always follows this notation:
a x 10b
Follow the steps below to see how 40,139,321 is written in scientific notation.
To find a, take the number and move a decimal place to the right one position.
Now, to find b, count how many places to the right of the decimal.
| New Number: | 4 | . | 0 | 1 | 3 | 9 | 3 | 2 | 1 |
| Decimal Count: | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
There are 7 places to the right of the decimal place.
Building upon what we know above, we can now reconstruct the number into scientific notation.
Remember, the notation is: a x 10b
a = 4.0139321
b = 7
Now the whole thing:
4.0139321 x 107
Check your work:
107 = 10,000,000 x 4.0139321 = 40,139,321
| 40,139,319 | 40,139,320 | 40,139,322 | 40,139,323 |
| 4.0139319 x 107 | 4.013932 x 107 | 4.0139322 x 107 | 4.0139323 x 107 |