Step by step
The question
Question: is 7866 divisible by 2, 3, 4, 6 and 9?
Divisible means it goes in exactly, with nothing left over.
1 Look at the last digit
7866 is 786 tens and 6.
2 goes into 10, so into every ten.
Only the last digit is left to check.
For 2: is it even: 0, 2, 4, 6 or 8?
The last digit is 6.
So yes.
2 Look at the last two digits
100 is 4 times 25.
So 4 goes into every hundred.
Only the last two digits are left: 66.
66 divided by 4 is 16, with 2 left over.
So no.
Careful!
Even is not enough for 4.
7866 is even, but 4 does not go into 66.
3 Add the digits
We add the digits: 7 + 8 + 6 + 6 is 27.
Why add the digits?
Each ten is 9 and 1 more.
Each hundred is 99 and 1 more.
3 and 9 go into the 9s and 99s.
What is left over is the sum of the digits.
For 3: 27 divided by 3 is 9, nothing left over.
So 3 goes into 7866.
For 9: 27 divided by 9 is 3, nothing left over.
So 9 goes into 7866.
4 Use 2 and 3
6 is 2 times 3.
So 6 goes in only when 2 and 3 both go in.
Both do.
So yes.
5 Write the answer
So 7866 is divisible by 2, 3, 6 and 9.
Not by 4.
6 Check
Let's check by dividing.
7866 divided by 2 is 3933, nothing left over.
Every yes divides exactly, and 4 leaves 2 over.
The tests were right!
Let's look back.
First: look at the last digit.
Then: look at the last two digits.
Then: add the digits.
Then: use 2 and 3.
Then: write the answer.
Last: check.