Q: How is the number 42,138,821 written in Scientific Notation?
A: 4.2138821 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 42,138,821 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 | . | 2 | 1 | 3 | 8 | 8 | 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 = 4.2138821
b = 7
Now the whole thing:
4.2138821 x 107
Check your work:
107 = 10,000,000 x 4.2138821 = 42,138,821
| 42,138,819 | 42,138,820 | 42,138,822 | 42,138,823 |
| 4.2138819 x 107 | 4.213882 x 107 | 4.2138822 x 107 | 4.2138823 x 107 |