Page 24 - BUSINESS MATHEMATICS MODULE 1 (WHOLE)_revised 10.20.2020
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Shortcuts in Addition*
Method 1. When adding integers, group and add at sight integers whose sum is 10.
10
Example 1. 4 + 3 + 6 + 7 + 5 = 25
10
Example 2. 3 34 10 3 4 8
10 5 10 22 7 6 5
5 86 4 2 4 10
2 63 1 3 1
10 6 10 47 10 9 5 3 10
4 21 1 4 7 .
25 273 2 7 6 8
Method 2. When adding more than two numbers of two digits each, add the tens
numbers first multiplied by 10, and add the unit numbers in sequence.
Example 1. Add 43 and 32.
Solution: Add 40 to 30 = 70
To 70 add 3 and 2 = 70 + 3 +2 = 75
Example 2. Add 73, 32, 51, and 23.
Solution: To the sum of 7, 3, 5, and 2 we have 17 multiplied by 10 = 170. (since
7,3, 5, and 2 are on the tens place)
Then add the units: 3, 2, 1, and 3.
73
32
51
23
17 × 10 =170
170 +3 +2 +1 +3 = 179
Or, we can do it this way:
70 + 3 = 73
30 + 2 = 32
50 + 1 = 51
20 + 3 = 23
170 + 9 = 179
170+3 + 2+ 1 +3 = 179
Page | 2.2 BUSINESS MATHEMATICS: Module 1
