1. Check whether 20664 is divisible by 72 or not?Solution:Divisibility rule of 72 :
If number is divisible by 8 and 9, then number is also divisible by 72.
Divisibility rule of 8 :
The last three digit is divisible by 8, then number is also divisible by 8.
Last 3 digit of 20664 is 664, which is divisible by 8.
`:.` 20664 is divisible by 8.
Divisibility rule of 9 :
The sum of the digits is divisible by 9, then number is also divisible by 9.
Sum of digits of 20664 is `2+0+6+6+4=18`, which is divisible by 9.
`:.` 20664 is divisible by 9.
20664 is divisible by 8 and 9.
`:.` 20664 is divisible by 72.
2. Check whether 23184 is divisible by 72 or not?Solution:Divisibility rule of 72 :
If number is divisible by 8 and 9, then number is also divisible by 72.
Divisibility rule of 8 :
The last three digit is divisible by 8, then number is also divisible by 8.
Last 3 digit of 23184 is 184, which is divisible by 8.
`:.` 23184 is divisible by 8.
Divisibility rule of 9 :
The sum of the digits is divisible by 9, then number is also divisible by 9.
Sum of digits of 23184 is `2+3+1+8+4=18`, which is divisible by 9.
`:.` 23184 is divisible by 9.
23184 is divisible by 8 and 9.
`:.` 23184 is divisible by 72.
3. Check whether 25488 is divisible by 72 or not?Solution:Divisibility rule of 72 :
If number is divisible by 8 and 9, then number is also divisible by 72.
Divisibility rule of 8 :
The last three digit is divisible by 8, then number is also divisible by 8.
Last 3 digit of 25488 is 488, which is divisible by 8.
`:.` 25488 is divisible by 8.
Divisibility rule of 9 :
The sum of the digits is divisible by 9, then number is also divisible by 9.
Sum of digits of 25488 is `2+5+4+8+8=27`, which is divisible by 9.
`:.` 25488 is divisible by 9.
25488 is divisible by 8 and 9.
`:.` 25488 is divisible by 72.
4. Check whether 20456 is divisible by 72 or not?Solution:Divisibility rule of 72 :
If number is divisible by 8 and 9, then number is also divisible by 72.
Divisibility rule of 8 :
The last three digit is divisible by 8, then number is also divisible by 8.
Last 3 digit of 20456 is 456, which is divisible by 8.
`:.` 20456 is divisible by 8.
Divisibility rule of 9 :
The sum of the digits is divisible by 9, then number is also divisible by 9.
Sum of digits of 20456 is `2+0+4+5+6=17`, which is not divisible by 9.
`:.` 20456 is not divisible by 9.
Hence 20456 is also not divisible by 72.
5. Check whether 22828 is divisible by 72 or not?Solution:Divisibility rule of 72 :
If number is divisible by 8 and 9, then number is also divisible by 72.
Divisibility rule of 8 :
The last three digit is divisible by 8, then number is also divisible by 8.
Last 3 digit of 22828 is 828, which is not divisible by 8.
`:.` 22828 is not divisible by 8.
Hence 22828 is also not divisible by 72.
6. Check whether 26725 is divisible by 72 or not?Solution:Divisibility rule of 72 :
If number is divisible by 8 and 9, then number is also divisible by 72.
Divisibility rule of 8 :
The last three digit is divisible by 8, then number is also divisible by 8.
Last 3 digit of 26725 is 725, which is not divisible by 8.
`:.` 26725 is not divisible by 8.
Hence 26725 is also not divisible by 72.
This material is intended as a summary. Use your textbook for detail explanation.
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