Chapter 1.5, Problem 42E

To determine

To calculate : The sum of the given expression:

  $-345+(-978)$

Answer to Problem 42E

  $\text{The sum of the given expression is -1323}\text{.}$

Explanation of Solution

Given information :

Consider the expression provided in the question:

  $-345+(-978)$

Calculation :

Evaluating the expression,

Both integers are negative, so the sum is negative;

  $-345+(-978)=-1323$

Estimating the sum by rounding off the integers to the nearest10;

  $-345\text{ rounded to nearest 10 is -350 and -978 rounded to nearest 10 is -980}\text{.}$

Therefore,

  $-350+(-980)=-1330.$

As both the integers are negative, the sum is also negative.

  $\text{1330 is a close estimation of 1323}\text{.}$