Chapter 8.1, Problem 80CCR

To determine

The value of the expression $20\cdot 7-2^4\cdot 5$

Answer to Problem 80CCR

The value of the expression is $60$

Explanation of Solution

Given:

  $20\cdot 7-2^4\cdot 5$

Concept Used:

Rules of Addition/ Subtraction:

• Two numbers with similar sign always get added and the resulting number will carry the similar sign.
• Two numbers with opposite signs always get subtracted and the resulting number will carry the sign of larger number.

Rules of Multiplication/ Division:

• The product/quotient of two similar sign numbers is always positive.
• The product/quotient of two numbers with opposite signs is always negative.

Calculation: In order to find the value of expression $20\cdot 7-2^4\cdot 5$ as below:

  $\begin{array}{c}{2}^4=2\ast 2\ast 2\ast 2=16\\ \text{So the experssion will become}\\ 20\cdot 7-2^4\cdot 5\\ =140-16\cdot 5\\ =140-80\\ =60\end{array}$

Thus, the value of the expression is $60$