Working with Percents
- Percents can be viewed as multipliers, which are their decimal forms, to simplify calculations.
- The basic principles include understanding that 'is' means equal, 'of' means multiply, converting percents to multipliers, and replacing unknowns with variables.
- To find an unknown percent, set up an equation with the percent as a variable and solve for it, remembering the result is the decimal form of the percent.
- For percents that are easily converted to fractions (e.g., 50%, 25%), using fractions can simplify calculations.
- Practice problems are provided to reinforce the understanding and application of these concepts.
Solutions to the Practice Problems:
1) What is 60% of 60
Let's translate this into a simple equation.
What --> "x" or what we are trying to find.
is --> "="
60% --> 60/100 or .6
of --> " *"
x = .6 * 60
x = 36
So all we did was multiply 0.6*60 and we get 36 as our answer.
2) 52 is 40% of what number?
is --> "="
40% --. 40/100 or .4
of --> " * "
what number --> x
52 = .4 * x
We divide both sides by 0.4 and we get X = 52/0.4 = 130
Let's do a check and make sure we did everything right.
3) 18 is what percent of 45?
Before we do anything math let's do a ball park. We know that half of 45 is 22.5 So without doing any math/computation we know that 50% of 45 is 22.5 so 18 is going to be less than 50>#/p###
is --> " ="
what percent --> x/100
of --> "*"
18 = (x/100) * 45
18/45 = x/100
.4 = x/100
40 = x
So 18 is 40% of 45.
Notice we can simply divide 18 by 45 to get .4
.4 is 40% in decimal form.
4) What is 50% of 128? [64]
This one you're just dividing 128 by 2.
x = .5 * 128 or 128/2
128/2 = 64