1. How to write a good mathematical explanation.
Today we will learn…
How to write a good mathematical explanation.
4-5: Writing to Explain
Vocabulary
Multiplication
Factor
Product

2. Vocabulary 3 X 5 = 15 factors product
Multiplication is an operation that gives the total number when you join equal groups.
3 X 5 = 15
factors
product
What do we call the numbers you are multiplying?
What is the answer to a multiplication problem called?

3. How to write a good math explanation:
DID YOU?
Tell the steps you did to solve the problem.
Explain why you did each step using the word because
Write your answer with a label
Use clear and easy to understand sentences
Go back and check to make sure your sentences answered the question

4. Let’s start with our problem (Use Cubes 1st)[ ]
Problem: The book store is selling books for $5.00 each. Ryan wants to buy 4 books. How much will this cost? [ ]
Decide on a strategy to solve the problem (repeated addition, equal groups, skip counting, make an array)
Let’s try using repeated addition to solve this problem.
= 20
You can demonstrate this problem with counters as well. Use either real counters or the EnVisions online counters to show.

5. Now it is time to write our explanation.
First, explain each step you did to solve the problem. For each step include the word because and an explanation of why you did that step.
Then, answer the question in a complete sentence. Make sure you answer includes a label.
First I did =20 because Ryan bought 4 books and they each cost $5.00.
The total cost of Ryan’s books is $20.
You can demonstrate this problem with counters as well. Use either real counters or the EnVisions online counters to show.

6. Try writing an explanation to this problem with a partner.[ ] [ ]
Problem #1: Ben bought 3 model car kits. Each car kit cost $6.00.
How much money did Ben spend on model car kits?
Decide on a strategy to solve the problem (repeated addition, equal groups, skip counting, make an array)
Start writing your explanation by explaining each step using the word because.
Write a sentence stating the answer to the question with a correct label.
You can demonstrate this problem with counters as well. Use either real counters or the EnVisions online counters to show.