Task 1
35 x 7 = 245
Determine the following products using a strategy you understand or a calculator.
1. 35 x .7 =
2. 3.5 x 7 =
3. .35 x 7 =
4. 350 x 7 =
5. 35 x 70 =
Which equations are equal to one another? Why is this the case?
How do the factors and products in equations 1 through 5 compare to the original equation (35 x 7 = 245)? Explain your thinking using precise mathematical vocabulary.
Task 2
Jake used the money he’d been saving to purchase a new mountain bike. The bike was on sale for $437, and the sales tax was 7%. The bicycle salesman informed Jake that the total was $742.90. Jake was unsure how this could be, as he had estimated the total to be much less and hadn’t prepared to pay that much for his new bike. Feeling deflated Jake went home without a new bicycle.
When Jake got home, he decided to do the math himself. He found that his original estimate was much closer to the correct total price than the salesman’s total. He also identified the mistake the salesman made.
1. Determine the correct total cost of Jake’s bike.
The formula for finding the total cost in this situation is…
total cost = bike price x .07 + bike price
2. Write a letter to the salesman explaining how you found the correct cost. Include the difference between the total he found and the correct total. Explain why this difference occurs.
Your explanation should include …
· equations that are accurate.
· an explanation for each equation presented.
· precise mathematical vocabulary when discussing the movement of a decimal in a number.
· an explanation of where you think the salesman made hi calculation error.