How do calculate fraction or irrational number percentage.
As we know that "10% of 100% is 0.10 or 0.1"
Don't stuck if it is difficult to understand you. You should to first understand how to calculate percentage from basics. Keep patience and let's start.
Let's Calculate:
| Percentage | In Numbers |
|---|---|
10 % of 100 |  |
| 20% of 100 |  |
| 90% of 100 |  |
| 100% of 100 |  |
Similar we should to assume that :
| Percentage in Probability Form | |
|---|---|
| Number |
Percentage |
| 0.1 is | 10% |
| 0.2 is | 20% |
| 0.3 is | 30 % |
| 0.4 is | 40% |
| 0.5 is | 50% |
| 0.6 is | 60% |
| 0.7 is | 70 % |
| 0.8 is | 80% |
| 0.9 is | 90% |
| 1.0 is | 100% |
| 0.79 is | 79% |
| 0.87 is | 87% |
Because by using the common mathematics identity, after the decimal point we can not count the number zero in some cases.
Condition 1. When just calculate percentage where the total number and sum of numbers are Given:
Example 1: Calculate the the percentage of number 
.
Solution:
How? Let's calculate:
Always used this formula to calculate percentage:
- -> Suppose that X representing a such number that you gain in your exam.
- -> And Y representing a total numbers of your exam.
Now, Suppose that you have gain 350 Marks out of 500.
So,
- X is 350 that you have gain on your exam.
- Y is total Marks of your exam.
Now put the values into the formulas
Similarly you can find out the Percentage that are asked in above Example.
x=4 and y=5
Now put it onto the Formula:
Shortcut Trick to calculate Percentages: ( Only use this trick for Calculating Probability's Question.)
-> Only divide X and Y don't multiply that by 100.
like this 
gives 0.8 that are similar to 80%, match this values through the Table 2.
Example 2 : Find Out the Percentage of the Following:
(A). 
(B). 
Solution (A):
Solution (B):
Similarly put the values into the formula,
Shortcut Trick to calculate Percentages : ( Only use this trick for Calculating Probability's Question.)
Just Divide Value of X and Value of Y, Don't Multiply that by 100.
Like this, 
= 0.428 .
Through the mathematical identity round the value after the decimal which is grater than 5.
That Means: 0.428 becomes 0.43 that are approximately similar to the 43%.
[Note refer Table 2 for more Knowledge]
Condition 2. When the percentage are given and we need to find out the total numbers that we have gain:
In this situation the percentage Formula becomes little changed
Example 3. Find out the 50% of the number 400?
Solution:
- P is 50%
- y is 400
Now, Put the values into the formula :
--> 200 Ans.
Example 4. Find out the 37% of the number 277?
Solution:
- P is 37%
- y is 277
Now, Put the values into the formula :
--> 102.49 Ans. 0r {102.5}
Condition 3 : How you get know which number you should to add to in given number which make that 100%. {This Condition is specially for Solving Probabilities problems.] {Very Important }
Example 5: How you get know which number make this number complete 100%?
Solution :
We know that = 0.428 or 0.43 { 43%}
So we should to add there some some number which give us 57% and after adding the both percentage gives 100%.
So Let's do it....
Step 1: Take the Divisor Value into two places...
,
Step 2: Now Subtract the divisor by Dividend...
7 - 3 = 4
Step 3: Now you have got new value which make 100 Percentage after Adding both numbers...
First Value is given in Example Five:
Second Value we have find out is : 
Step 4: Now add the both Values:
----> = 0.428 or { 0.43 }
-----> 
= 0.57
Adding Both Values = 0.57 + 0.43 = 1 { 1 is similar to 100% when we solving Problems in Probabilities.}
Example 6: Find the percentage of the Following to make that 100 Percentage:
(A) 
(B) 
Sloution: (A)
Step 1: Take the Divisor Value into two places...
,
Step 2: Now Subtract the divisor by Dividend...
9 - 2 = 7
Step 3: Now Adding the Given value and New Value...
First Value is given in Example Five:
First Value is given in Example Five: 
Step 4: Now add the both Values :
----> 
= 0.22
----> 
= 0.777 or{ 0.78 }
Adding Both Values = 0.22 + 0.78 = 1 { 1 is similar to 100% when we solving Problems in Probabilities.}
Solution: (B)
Note: This problem will solve similar to previous, you can solve it by yourself through taking the reference of above solution.
[Hint 1 : 6 / 9 = 0.67 and 3 / 9 =0.33 ]
[Hint 2: We always round the value of decimal number which greater than 5.]
[Example 1: 0.779999 can we write as 0.78]
[Example 2: 0.447 can we write as 0.45]
[Example 3: 0.355 can we write as 0.355 "Don't Change it Because it should be grater than 5" but it is not.]
If Your Are Confused so you can do comment below for Solution.....