Page 25 - BUSINESS MATHEMATICS MODULE 1 (WHOLE)_revised 10.20.2020

Course Guide

Checking Addition
To find out the correctness of the sum in addition, we may add the numbers in a

different way. The simplest and most common method of checking the accuracy of addition is
the reverse-order check. After finding the sum downward, we can do the following.

1. Add each column upward M1_L1
2. Write the sums to the right of the problem

3. If the sums obtained agree, check off each answer.

Example: 458 14 = the sum of the first column
321 13 = the sum of the second column
742 21 = the sum of the third column
613 2134 = Sum M1_L2
2134
Another way of doing the reverse-order check, after finding the sum downward, is to

do the following
1. Add each column upward Example: 2134
458
2. Write the sum above the problem
321
3. If the two sums agree, the answer is probably correct. 742
613
2134
Horizontal and Vertical Addition

The process of addition may be done vertically (up and down) and horizontally
(across). Many business firms require their employees to add both vertically and horizontally.

This way, they can easily check the accuracy of the addition. The sum of the vertical totals
must equal the sum of the horizontal totals.

Example: Sigma Manufacturing Company Warehouse Employees
Location Receiving Shipping Totals
Novaliches 5 7 −
Makati 18 20 −
Las Piñas 6 8 −
TOTALS − − −

Solution: Sigma Manufacturing Company Warehouse Employees
Location Receiving Shipping Totals
Novaliches 5 7 12
Makati 18 20 14
Las Piñas 6 8 14
TOTALS 29 35 64
A total of 64 is the company's total number of warehouse employees. Both the
vertical totals (12 + 38 + 14 = 64) and the horizontal totals (29 + 35 64) should have a sum of
64.
LESSON 2: FUNDAMENTAL OPERATIONS 2.3 | P a g e