standard_description: Interpret multiplication as scaling (resizing), by:
- Explaining why multiplying a given number by a fraction greater than 1 results in a product greater than the given number (recognizing multiplication by whole numbers greater than 1 as a familiar case); explaining why multiplying a given number by a fraction less than 1 results in a product smaller than the given number; and relating the principle of fraction equivalence a/b = (n×a)/(n×b) to the effect of multiplying a/b by 1.
- Comparing the size of a product to the size of one factor on the basis of the size of the other factor, without performing the indicated multiplication.
problem_activity: Problem 1
Act 1: Look at the following image -
[IMG]
Then watch the video
Piggy Bank
.
a.   What do you notice? What do you wonder?
b.   Is there enough money to purchase the paint set? Make an estimate for how much money is in the piggy bank.
Problem 2
Act 2: Use the following information to determine whether there is enough money in the piggy bank to buy the paint set –
There are 70 nickels in the piggy bank.
There are 64 quarters in the piggy bank.
There are 105 dimes in the piggy bank.
There are 230 pennies in the piggy bank.
Problem 3
Act 3: See the solution below –
[IMG]
Was your answer reasonable? Why or why not?
Problem 4
Act 4 (the sequel): If she buys the paint set, how much money will she have left over?


aligns: no