Chapter 1.1, Problem 34HP

(a)

To determine

To write: two different expressions for the given statement

Answer to Problem 34HP

The first expression is $\left(60-20\right)÷2$ and the second expression is $4\times 10-25+5$

Explanation of Solution

Given:

Each with more than one operation thathas a value of 20

Calculation:

Let first consider the expression,

  $\left(60-20\right)÷2$

To show that its value is 20, evaluate it according to the order of operations.

So, first solve the brackets.

  $\left(60-20\right)÷2=\left(40\right)÷2=40÷2$

Now, divide

  $\left(60-20\right)÷2=\left(40\right)÷2=20$

Thus, our first expression is

  $\left(60-20\right)÷2$

Now, consider the expression.

  $4\times 10-25+5$

To show that its value is 20, evaluate it according to the order of operations.

Now, multiply.

  $4\times 10-25+5=40-25+5$

Now add or subtract in order from left to right.

Since, going from left to right, first operation is subtraction, so subtract first.

  $\begin{array}{l}4\times 10-25+5=40-25+5\\ =15+5\end{array}$

Finally add to obtain

  $4\times 10-25+5=15+5=20$

Thus, our second expression is

  $4\times 10-25+5$

Conclusion:

Hence, the first expression is $\left(60-20\right)÷2$ and the second expression is $4\times 10-25+5$