Modeling Two-Step Money Problems with Tape Diagrams
This Grade 4 Eureka Math skill teaches students to use tape diagrams to model and solve two-step money word problems. Students first add individual costs to find a total, then subtract that total from a starting amount to find the change. For example, if Josie buys a $3.45 notebook and a $2.80 pack of pens and pays with a $10.00 bill, the tape diagram shows total cost of $6.25 and change of $3.75. This visual problem-solving method is covered in Chapter 33 of Eureka Math Grade 4.
Key Concepts
A tape diagram can model a multi step problem where a total cost ($C$) is subtracted from an initial amount ($A$) to find the remaining amount or change ($R$). First, find the total cost by adding individual items: $C = \text{cost} 1 + \text{cost} 2$. Then, find the change: $R = A C$.
Common Questions
How do you use a tape diagram to solve a two-step money problem?
Draw a tape for the starting amount (e.g., money paid). Inside it, show a section for total cost and a section for change. First calculate the total cost, then subtract from the starting amount.
How do you find total cost in a two-step money problem?
Add the prices of all items. For a $3.45 notebook and a $2.80 pack of pens: $3.45 + $2.80 = $6.25.
How do you find the change after a purchase?
Subtract the total cost from the amount paid. If the total cost is $6.25 and you paid $10.00, the change is $10.00 - $6.25 = $3.75.
Why use a tape diagram for money word problems?
A tape diagram makes the two steps visual. You can see exactly how the total amount is split between what was spent and what is returned as change, reducing errors.
What formula does a two-step money tape diagram represent?
R = A - C, where A is the starting amount, C is the total cost (sum of individual prices), and R is the remaining amount or change.