How to get better with probabilities

What kind of things in probability are you trying to get better with?
One of the most important things to know what to do in probabilities are converting fractions to decimals to percentages. 
As a reminder, you can do this by taking a fraction like y/x and using it for division.
y/x becomes y divided by x. The numerator becomes the dividend and the denominator becomes the divisor. Once you divide this you'll get the fraction as a decimal. 
To make this decimal a percent you simply take the decimal and move it two places to the right.

Don't know how to find out what the fraction is in probabilities? Do this.
Say there's a bag with fifteen crayons. 7 crayons are yellow, 4 crayons are red, and 4 crayons are green. These would be the fractions:
Yellow = 7/15
Red = 4/15
Green = 4/15

Notice that the total amount of crayons, 15, serves as a denominator for every problem while the specific amount of each color crayon serves as the numerator.
Now lets use those skills with converting fractions into decimals and percentages to find out what the chances of picking out each color are.

Yellow: 7/15 = about 0.46 (6 repeating) = about 46.66%
Red: 4/15 = about 0.26 (6 repeating) = about 26.66%
Green: 4/15 = about 0.26 (6 repeating) = about 26.66%

So what's the chance of picking a red or green crayon? 
4/15 + 4/15 = 8/15
8/15 = about 0.53 (3 repeating) = about 53.33%

Hope this can help you.