Page 5 - Arithmetic

31, 67, 99, and so on
Even numbers
Any integer that doesn’t leave a remainder on dividing by 2 is called an even number.
For example,
22, 80, 48, and so on
REMEMBER:
Odd numbers end with 1,3, 5, 7, and 9 Even numbers end with 0, 2, 4, 6, and 8
Rules of divisibility
Use the following table for the divisibility rule.
A number is divisible by 2
3
4
5 6 8
9 10
12
If
It ends in 0, 2, 4, 6, and 8
The sum of the numbers divisible is by 3
The numbers which are formed by the last two digits are divisible by 4
Itendsin0and5
It’s divisible by both 2 and 3
The numbers which are formed by the last three digits are divisible by 8
The sum of the numbers is divisible by 9
It ends in 0
It’s divisible by both 3 and 4
11
The difference of the sum of the digits at odd places and the sum of the digits at even places is either 0 or divisible by 11
Worked Example 2
Is 17424 divisible by 11?
Solution:
The sum of the digits at odd places = 1+ 4+ 4 = 9 The sum of the digits at even places =7 + 2 = 9 Difference = 9-9 = 0
So, 17424 is divisible by 11.
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Arithmetic Concept