Vocabulary
Define the term 'ratio'
A set of numbers that associates two or more quantities.
How can you find 50% of any number?
Divide by 2, or multiply by 1/2.
A candy store sells small pieces of candy, 12 pieces for $4.
What is the cost per piece of candy?
$0.33
Convert 27 gallons to cups
432 cups
Define the term 'percent'
A percent is a rate per 100.
Define the term 'equivalent ratio'
Two ratios are equivalent if you can multiply each of the numbers in the first ratio by the same factor to get the numbers in the second ratio.
How can you find 75% of any number?
Divide by 4, and multiply by 3 (or multiply by 3/4).
Watermelon is on sale for $4 per pound.
How much would 5 pounds cost?
$20
Convert into minutes
9 hours 30 minutes
570 minutes
The value of 8 dimes is % of the value of a dollar.
80%. 8 dimes are 80 cents, and a dollar is 100 cents, so 8 dimes are 80% the value of 1 dollar.
Define the term 'per'
The word per means “for each.”
How long is 75% of 60 minutes?
45 minutes
The fastest elevators in the Burj Khalifa can travel 330 feet in just 10 seconds. How far does the elevator travel in 11 seconds? Explain your reasoning
If the elevator travels 330 feet in 10 seconds, then it is traveling 33 feet per second. Multiplying 33 by 11 gives 363 feet in 11 seconds.
The conversion rates between kilograms and pounds are:
1 kg ≈2.2 lbs
1 lb ≈ 0.454 kg
How many kilograms is a backpack that weighs 6 pounds?
2.724 kg
Andre also has a puppy that weighs 9 pounds. The vet says that this puppy is now at about 30% of its adult weight. What will be the adult weight of Andre’s puppy?
30 pounds.
Define the term 'multiplicative relationship'
A relationship where two quantities can be expressed as multiples of each other.
Johanna saves 60% of her weekly paycheck. How much does she save if she earns $120.
$72
You are shoveling snow from the sidewalks around your neighborhood after a big snowstorm. You work at a steady rate, shoveling 10 feet of sidewalk in 40 minutes.
You are shoveling snow from the sidewalks around your neighborhood after a big snowstorm. You work at a steady rate, shoveling 10 feet of sidewalk in 40 minutes.
300 minutes
A state fair help a heaviest-pumpkin contest. The winning pumpkin weighed 2,050 pounds. What is the weight, in ounces, of the winning pumpkin?
32,800 ounces
You walk out of school with $0.75 in your pocket. On your way home, you pick up 5 pennies and a dime and put them in your pocket. What percent of a dollar do you have in your pocket?
90 %
Define the term 'conversion rate'
A rate that can be used to convert one unit of measure, such as pounds, to another unit of measure, such as ounces.
What is 20% of 210? Explain how you can find 20% of any number using mental math.
42
To find 20% of any number using mental math, first find 10% of the number by dividing by 10, then take twice this value to get 20 %.
Jack and Priya are setting up folding chairs for their school’s weekly Community Meeting. Jack can unfold and set up 55 chairs in 20 minutes. Priya can unfold and set up 44 chairs in 15 minutes. Who works at the faster rate? Justify your answer.
Priya works at a faster rate. She unfolds and sets up 176 chairs in one hour, compared to Jack's 165 chairs in one hour.
If the speed limit is 80 kilometers per hour, and Elena’s mom was driving 75 miles per hour, was she speeding? By how much?
Yes, she was speeding by about 25 miles per hour or about 40 kilometers per hour.
Order these three values from least to greatest. Explain or show your reasoning.
65% of 80
82% of 50
170% of 30
The least is 82% of 50, because (0.82) · 50 = 41. Next is 170% of 30, because (1.7) · 30 = 51. The greatest is 65% of 80, (0.65) · 80 = 52.