Using the distributive property provides a shortcut for calculating the final amount in situations that involve adding or subtracting a fraction of the original amount.
For example, one day Clare runs 4 miles. The next day, she plans to run that same distance plus half as much again. How far does she plan to run the next day?
Tomorrow she will run 4 miles plus 21 of 4 miles. We can use the distributive property to find this in one step: 1⋅4+21⋅4=(1+21)⋅4
Clare plans to run 6 miles, because 121⋅4=6.
This works when we decrease by a fraction, too. If Tyler spent x dollars on a new shirt, and Noah spent 31 less than Tyler, then Noah spent 32x dollars since x−31x=32x.
Apply the properties of operations to generate equivalent expressions.
Compute unit rates associated with ratios of fractions.
Use ratio and rate reasoning to solve real-world and mathematical problems.
Understand that rewriting an expression in different forms in real-world and mathematical problems can reveal and explain how the quantities are related.
Recognize and represent proportional relationships between quantities.
Use proportional relationships to solve multistep ratio and percent problems.