Maths Private Lessons by Sir Emma

Good morning. Let’s continue our lessons on divisibility of numbers. But before we continue let’s have a recap of what we talked about yesterday.

In summary

1. Any number that has its last digit as 2,4,6,8,0 can be divided by 2 exactly.

2. Any number that has the sum of its digits to be a multiple of 3 is divisible by 3 .

3. Any number that has its last 2 digits as a multiple of 4 is divisible by 4.

Bonus fact

Any number divisible by 4 is divisible by 2 but not vice versa . And the reason is simple , 2 is a factor of 4 and not vice versa .

So let’s start with today’s lesson ..

DIVISIBILITY BY 2
Any number that has its last digit as an even number (ie 2,4,6,8,0 ) is divisible by 2 . For example 71352 and 2550 are divisible by 2 exactly because their last digit is an even number ( 2 and 0 ) respectively.

DIVISIBILITY BY 3
A number is divisible by 3 exactly when the sum of the digits of the number is a multiple of 3. For example 12453 is divisible by 3 exactly because the sum of the digits (1+2+4+5+3 = 15) is a multiple of 3 . Same as 561111 , 20022 and many others.

DIVISIBILITY BY 4
A number is divisible by 4 exactly when the last 2 digits of the number is a multiple of 4 (ie 04,08,12,16,20,24 ...). For example: 33148 is divisible by 4 exactly since its last 2 digits is 48 which is a multiple of 4. Same as 11240, 46344 and many others