Chapter 4.1, Problem 32PPS

To determine

To evaluate: $13·39$

Answer to Problem 32PPS

  $507$

Explanation of Solution

Given information:

  $13·39$

Concept Used:

Distributive Property: The product sum or difference of two or more numbers inside a parentheses with another number outside the parentheses is equivalent to the sum or difference of product of number outside the parentheses with each number inside the parenthesis. i.e.-

  $a\left(b+c-d\right)=ab+ac-ad$

Calculation:

  $13·39=507$

We can also solve it using distributive property.

  $39$ can be written as $40-1$

The expression $13·39$ will now become

  $13\left(40-1\right)$

We can write the given expression in distributive form as-

  $13\left(40-1\right)=13\left(40\right)-13\left(1\right)$

This can further be evaluated as-

  $\begin{array}{l}13\left(40\right)-13\left(1\right)=520-13\\ \Rightarrow 13\left(40\right)-13\left(1\right)=507\end{array}$

Both the answers match