### Home > MC2 > Chapter 5 > Lesson 5.1.3 > Problem5-39

5-39.

Alex is trying to simplify the expression $- 1 \frac { 1 } { 4 } + ( 2 \frac { 1 } { 2 } ) + ( 3 \frac { 1 } { 4 } )$. He started by rewriting it like this:

$\left. \begin{array} { l } { - 1 + ( - \frac { 1 } { 4 } ) + 2 + \frac { 1 } { 2 } + 3 + \frac { 1 } { 4 } } \\ { ( - 1 + 2 + 3 ) + ( - \frac { 1 } { 4 } + \frac { 1 } { 4 } + \frac { 1 } { 2 } ) } \end{array} \right.$

1. Why might he have regrouped the expression in this way?

What are the differences between the two groups of numbers?

Does it make the equation any easier to solve?

Regrouping simplifies the arithmetic.

2. Simplify the expression. What is the result?

First simplify the terms in parentheses.

$4 \frac{1}{2}$

3. What property was Alex using when he rewrote the problem?

What mathematical actions did Alex take?
What property is this?

4. Use this strategy to regroup the expression $\frac { 3 } { 10 } + 2 \frac { 1 } { 10 } + ( - 1 \frac { 2 } { 5 } )$ and find the result.