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working with percents



summary
mastering percents involves understanding their application as multipliers, translating percentages into decimals for calculations, and leveraging fractions for simpler percentages.
  • percents as multipliers are a fundamental concept, where 'is' translates to equals and 'of' signifies multiplication.
  • to solve percent problems, convert the percentage to its decimal form, use variables for unknowns, and perform the necessary arithmetic operations.
  • finding an unknown percent involves setting up an equation with the percent as a variable multiplier and solving for it.
  • for percentages that are easily represented as fractions (e.g., 50%, 25%), converting to fractions can simplify calculations.
  • practice problems are provided to reinforce the concepts and methods discussed.
chapters
00:21
percents as multipliers
00:51
solving for unknowns
01:39
finding the percent
02:15
percents and fractions

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