Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
2. Properties of Real Numbers
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Exercise 67 Page 16

Think of a situation that would require us to calculate a mathematical expression that can be simplified.

See solution.

Let's start by writing an example problem.

Example Problem

Imagine that we have 4 different duct tapes rolls. They are all 325 centimeters long, but their widths are different. The widths are 1, 2, 2, and 5 centimeters.

Roll 1 Roll 2 Roll 3 Roll 4
Length (cm) 325 325 325 325
Width (cm) 1 2 2 5


We want to find the total area we can cover using all the tape rolls. How can we find it?

Solving the Example Problem

The tape pieces will be like very long rectangles. The area A of a rectangle is the product of its length l and its width w. A = l * w The total area will be equal to the sum of all the individual areas.
A_T= A_1 +A_2+A_3+A_4
A_T= l_1* w_1 + l_2* w_2 + l_3* w_3 +l_4* w_4
A_T = 325* 1 + 325* 2+ 325* 2 +325* 5
A_T = 325 + 650 +650 + 1625
A_T = 3250
Now let's think — is there an easier way than calculating all the products and then adding them? Notice that the sum of the products above resembles the Distributive Property. a(b+c+d+e) = ab + ac + ad+ ae We can rewrite the sum of the products and find our result in a easier a way.
A_T = 325* 1 + 325* 2 + 325* 2 + 325* 5
A_T= 325(1+2+2+5)
A_T=325(10)
A_T=3250
Notice that this is only one example of applications of the Properties of Real Numbers. There are infinitely many cases in which we can use them in algebraic problems to simplify algebraic expressions.