Write an expression for the amount of change you will get...

Name: Problem 34, Chapter 1: Algebra 1 Common Core
Uploaded: 2020-07-02T19:20:30-08:00
Duration: 2 min 50 s
Channel: Chelsi Boswell
Description: Write an expression for the amount of change you will get when you pay for a purchase p with a 20 dollar bill. Make table to find the amounts of change you will get for purchases of 11.59 dollar, 17.50 dollar, 19.00 dollar and 20.00 dollar.

Write an expression for the amount of change you will get when you pay for a purchase p with a 20 dollar bill. Make table to find the amounts of change you will get for purchases of 11.59 dollar, 17.50 dollar, 19.00 dollar and 20.00 dollar.

Key Concepts

Construction of Data Tables

Creating a table is a method used to organize and display information in a clear and systematic way. In this case, constructing a table helps to neatly summarize the purchase amounts alongside their corresponding change, making it easier to compare multiple results and understand the relationship between the purchase price and the change received.

Evaluation of Expressions

Evaluating an expression means substituting specific numerical values into an algebraic expression and carrying out the arithmetic operations to obtain a result. Here, this concept is applied by substituting particular purchase values into the expression that represents the change, thereby yielding the exact amounts of change for those specific purchases.

Subtraction as a Mathematical Operation

Subtraction is the process of determining the difference between two numbers. In this scenario, it is used to calculate the amount of change by subtracting the cost of the purchase from the amount of money given. Understanding subtraction is crucial as it is one of the basic arithmetic operations that are used extensively in both simple and complex calculations.

Algebraic Expression Formulation

This concept involves writing a formula to represent a relationship between quantities. In the context of the problem, it means expressing the change received as a function of the purchase price, which is achieved by subtracting the purchase price from the total amount paid. This approach is foundational in algebra because it allows for the abstraction of numerical relationships that can be applied universally.

Transcript

00:02 Okay, in this problem, we're creating an expression and a table to find out how much change we get back if we make a purchase and use a $20 bill.

00:12 So the first thing we're going to do is identify our two unknowns.

00:15 They've already told us that p represents the purchase.

00:23 And i'm going to say that c represents the change we get back.

00:28 Because that's what we want to know.

00:30 How much change are we going to get back? so we need to create an expression that represents this situation.

00:35 We're paying the $20 bill.

00:38 And with change, change is what you get back after a purchase.

00:41 So there's some subtraction happening in there.

00:44 So we could say that our change that we're going to get back is equal to 20 minus p.

00:52 So i'm giving them a $20 bill.

00:55 They're going to take out whatever money i used for the purchase.

00:58 And then they're going to give me some change back.