Standard Form In Mathematics
This article will give you a detailed guide on expressing numbers in a unique form known as the standard form. We will illustrate this topic using several worked examples to ease understanding. Ensure that you read this article to the end.
What Is Standard Form?
Standard form is a unique way of expressing very large or very small numbers, e.g. 1,222,333,645 or 0.0009898, using a shorter and easily written format. It is usually expressed mathematically as:
a x 10n
Where;
a is a positive or negative number between 1 and 9
n is a positive or negative integer
The standard form makes numbers that were otherwise very large to write down or compute small and easier to use. It uses an index (powers) to express numbers in an easily understood format.
Step-by-step Guidelines For Converting Numbers To Standard Form
We shall use some worked examples to show you how to convert ordinary numbers to standard forms.
Example
Write the following numbers in their standard form:
- 5187362000
- 345674
- 420.46
- 00000008776897
- 002389978
- 23.34
Solution
- 5187362000
Step one: Check the number’s nature, that is, whether it is positive or negative. In our case, 5187362000 is a positive number.
Step Two: Add a decimal point after the first integer in the number. In our case, we shall add a decimal point after 5
5.187362000
Step Three: Recall that the general formula for standard form is a x 10n. Count the number of digits (including 0) after the decimal point. The number of digits serves as the power or index of the standard form. In this question, our index is 109
Step Four: Write out the non-zero digits and then multiply by the index derived above.
= 5.187362 x 109
- 345674
We are going to repeat all the steps above.
3.45674
Number of digits after the decimal point = 5
= 3.4 x 105
Also Recommended:
Indices: Meaning, Laws, And Worked Examples
Logarithm: Definition, Laws, And Worked Examples
Changing The Subject Of The Formula
- 420.46
This question poses an unusual problem; it comes with a decimal point already. To solve this quickly, you have to recall your number line.
As a positive number, you are required to express the standard form in one decimal place. Therefore, to solve this, you will count the number of places you moved back to get the first decimal point. That will serve as your index
420.46
= 4.2046 x 102
- 00000008776897
To solve this, you have to follow these steps
Step one: Move the decimal point to the first non-zero digit
Step two: count the number of 0 before the first non-zero digit; the number is the index. In this case, the number is 8. However, you will express the index as 10-8 to indicate that there are zeros ahead of the number.
This is so because; 0.00000008776897 = 8.776897/100000000
Step three: write out the full number
= 8.776897 x 10-8
You can approximate it to two decimal places
= 8.78 x10-8
- 002389978
= 2.39 x 10-3
- 23.34
= 2.334 x 101
Converting From Standard Form To Ordinary Form
You can also convert from standard form to ordinary numbers.
Example: convert 4.2 x 102 and 3.4 x 10-3 to ordinary form
Solution
(i) 102 = 10 x 10 = 100
4.2 x 100 = 420
(ii) 10-3 = 1/10 x 1/10 x 1/10 = 0.001
3.4 x 0.001 = 0.0034
Things To Note About Standard Form
- Any number can be converted into standard form regardless of whether they are very large or very small. You will convert it as much as you know and follow the conversion rules accordingly.
- In the standard form general formula, a can be either a whole number or a decimal fraction, and n can be zero.
- You need to have a sound knowledge of the number line.
- A good knowledge of indices’ power law is needed to solve arithmetic problems involving this form quickly.
- Standard form is very important to astronomers, as their field requires the computation of both very large and very small numbers.
This article clearly shows you how to express numbers in their standard forms. If you have further questions, comments, or inquiries about this article, use the comment box below. Also, subscribe to this blog for more interesting educational guides like this.
