Answer:
Let's see each case.
a) 2
We know that a number is divisible by two if it ends in {0, 2, 4, 6, 8}
In our case, we have 240,720
We can see that it ends with a zero, so it is divisible by 2.
b) 3
A number is divisible by 3 only if the sum of its digits is a multiple of 3.
For our number, the sum of the digits gives:
2 + 4 + 0 + 7 + 2 + 0 = 2 + 4 + 7 + 2 = 6 + 9 = 15
15 is a multiple of 3, then 15 is divisible by 3.
then 240,720 is divisible by 3.
c) 4
A number is divisible by 4 if the last two digits form a number that is divisible by 4.
In this case, the last two digits are 2 and 0, so they form the number 20
and we know that 20 = 4*5 is a multiple of 4.
then 20 is divisible by 40
then 240,720 is divisible by 4
d) 5
A number is divisible by 5 if it ends in 0 or 5.
Our number ends in a 0, so it is divisible by 5.
e) 6
A number is divisible by 6 if it is divisible by 2 and 3.
We already know that our number is divisible by 2 and 3, so we can conclude that it is also divisible by 6.
f) 8
A number is divisible by 8 if, in the case where the hundreds digit is odd, the number obtained from the last two digits plus 4 must be divisible by 8.
in the case where the hundreds digit is even, the number formed by the last two digits must be divisible by 8.
In our case the hundreds digit is 7, so it is odd, so we will use the first criteria.
The last two digits form the number 20
if we add 4, we get:
20 + 4 = 24
And 24 is a multiple if 8: 8*3 = 24
Then 24 is divisible by 8, then 240,720 is divisible by 8.
g) 9
Similar for the case of the 3, a number is divisible by 9 if the sum of its digits is divisible by 3.
We know that the sum of the digits of our number is 15, which is not divisible by 9, then our number is not divisible by 9
h) 10
A number is divisible by 10 if the last digit is a zero.
In this case the last digit is a zero, so 240,720 is divisible by 10.
i) 11
A number is divisible by 11 if:
starting from the left, you need to add and subtract each subsequent digit, if this is divisible from 11, then the original number is divisible by 11.
Then for 240,720 we have:
2 - 4 + 0 - 7 + 2 - 0 = -2 - 5 = -7
-7 is not divisible by 11, so our number is not divisible by 11