MemberFebruary 4, 2021 at 1:29 pm
The cost of 1 lb of butter at Store A is $3.60. The cost of 1 lb of butter at Store B is $4.50.
Store A butter is 4/5 the price of Store B butter..
Store B butter is 5/4 the price of Store A butter.
At my local gas station, the price of gas is $2.48 per gallon.
A customer receives 6/8 of a gallon for $1.86.
For $12.40 a customer may receive 5 gallons of gas.
Both use multiplicative thinking to determine the relationship between quantities. The multiplicative comparison example shows different quantities within the same attribute, making the quantities comparable to one another. The composed unit example shows different quantities with different attributes. These attributes are incomparable, yet the quantities increase and decrease by the same rate.